diff --git a/Meta/Lagom/Tools/CodeGenerators/LibLocale/GenerateDateTimeFormatData.cpp b/Meta/Lagom/Tools/CodeGenerators/LibLocale/GenerateDateTimeFormatData.cpp
index 56f7ed98ccf..9eb5fb687ac 100644
--- a/Meta/Lagom/Tools/CodeGenerators/LibLocale/GenerateDateTimeFormatData.cpp
+++ b/Meta/Lagom/Tools/CodeGenerators/LibLocale/GenerateDateTimeFormatData.cpp
@@ -1793,13 +1793,13 @@ static void convert_calendar_fields(SourceType const& source, TargetType& target
 }
 
 struct CalendarPatternImpl {
-    ErrorOr<CalendarPattern> to_unicode_calendar_pattern() const {
+    CalendarPattern to_unicode_calendar_pattern() const {
         CalendarPattern calendar_pattern {};
 
-        calendar_pattern.skeleton = TRY(String::from_utf8(decode_string(skeleton)));
-        calendar_pattern.pattern = TRY(String::from_utf8(decode_string(pattern)));
+        calendar_pattern.skeleton = MUST(String::from_utf8(decode_string(skeleton)));
+        calendar_pattern.pattern = MUST(String::from_utf8(decode_string(pattern)));
         if (pattern12 != 0)
-            calendar_pattern.pattern12 = TRY(String::from_utf8(decode_string(pattern12)));
+            calendar_pattern.pattern12 = MUST(String::from_utf8(decode_string(pattern12)));
 
         convert_calendar_fields(*this, calendar_pattern);
         return calendar_pattern;
@@ -1823,14 +1823,14 @@ struct CalendarPatternImpl {
 };
 
 struct CalendarRangePatternImpl {
-    ErrorOr<CalendarRangePattern> to_unicode_calendar_range_pattern() const {
+    CalendarRangePattern to_unicode_calendar_range_pattern() const {
         CalendarRangePattern calendar_range_pattern {};
 
         if (field != -1)
             calendar_range_pattern.field = static_cast<CalendarRangePattern::Field>(field);
-        calendar_range_pattern.start_range = TRY(String::from_utf8(decode_string(start_range)));
+        calendar_range_pattern.start_range = MUST(String::from_utf8(decode_string(start_range)));
         calendar_range_pattern.separator = decode_string(separator);
-        calendar_range_pattern.end_range = TRY(String::from_utf8(decode_string(end_range)));
+        calendar_range_pattern.end_range = MUST(String::from_utf8(decode_string(end_range)));
 
         convert_calendar_fields(*this, calendar_range_pattern);
         return calendar_range_pattern;
@@ -1863,13 +1863,13 @@ struct CalendarRangePatternImpl {
 
     generator.append(R"~~~(
 struct CalendarFormatImpl {
-    ErrorOr<CalendarFormat> to_unicode_calendar_format() const {
+    CalendarFormat to_unicode_calendar_format() const {
         CalendarFormat calendar_format {};
 
-        calendar_format.full_format = TRY(s_calendar_patterns[full_format].to_unicode_calendar_pattern());
-        calendar_format.long_format = TRY(s_calendar_patterns[long_format].to_unicode_calendar_pattern());
-        calendar_format.medium_format = TRY(s_calendar_patterns[medium_format].to_unicode_calendar_pattern());
-        calendar_format.short_format = TRY(s_calendar_patterns[short_format].to_unicode_calendar_pattern());
+        calendar_format.full_format = s_calendar_patterns[full_format].to_unicode_calendar_pattern();
+        calendar_format.long_format = s_calendar_patterns[long_format].to_unicode_calendar_pattern();
+        calendar_format.medium_format = s_calendar_patterns[medium_format].to_unicode_calendar_pattern();
+        calendar_format.short_format = s_calendar_patterns[short_format].to_unicode_calendar_pattern();
 
         return calendar_format;
     }
@@ -2045,11 +2045,11 @@ static Optional<Calendar> keyword_to_calendar(KeywordCalendar keyword)
     }
 }
 
-ErrorOr<Vector<HourCycle>> get_regional_hour_cycles(StringView region)
+Vector<HourCycle> get_regional_hour_cycles(StringView region)
 {
     auto region_value = hour_cycle_region_from_string(region);
     if (!region_value.has_value())
-        return Vector<HourCycle> {};
+        return {};
 
     auto region_index = to_underlying(*region_value);
 
@@ -2057,7 +2057,7 @@ ErrorOr<Vector<HourCycle>> get_regional_hour_cycles(StringView region)
     auto const& regional_hour_cycles = s_hour_cycle_lists.at(regional_hour_cycles_index);
 
     Vector<HourCycle> hour_cycles;
-    TRY(hour_cycles.try_ensure_capacity(regional_hour_cycles.size()));
+    hour_cycles.ensure_capacity(regional_hour_cycles.size());
 
     for (auto hour_cycle : regional_hour_cycles)
         hour_cycles.unchecked_append(static_cast<HourCycle>(hour_cycle));
@@ -2125,59 +2125,59 @@ static CalendarData const* find_calendar_data(StringView locale, StringView cale
     return lookup_calendar(*default_calendar);
 }
 
-ErrorOr<Optional<CalendarFormat>> get_calendar_date_format(StringView locale, StringView calendar)
+Optional<CalendarFormat> get_calendar_date_format(StringView locale, StringView calendar)
 {
     if (auto const* data = find_calendar_data(locale, calendar); data != nullptr) {
         auto const& formats = s_calendar_formats.at(data->date_formats);
-        return TRY(formats.to_unicode_calendar_format());
+        return formats.to_unicode_calendar_format();
     }
-    return OptionalNone {};
+    return {};
 }
 
-ErrorOr<Optional<CalendarFormat>> get_calendar_time_format(StringView locale, StringView calendar)
+Optional<CalendarFormat> get_calendar_time_format(StringView locale, StringView calendar)
 {
     if (auto const* data = find_calendar_data(locale, calendar); data != nullptr) {
         auto const& formats = s_calendar_formats.at(data->time_formats);
-        return TRY(formats.to_unicode_calendar_format());
+        return formats.to_unicode_calendar_format();
     }
-    return OptionalNone {};
+    return {};
 }
 
-ErrorOr<Optional<CalendarFormat>> get_calendar_date_time_format(StringView locale, StringView calendar)
+Optional<CalendarFormat> get_calendar_date_time_format(StringView locale, StringView calendar)
 {
     if (auto const* data = find_calendar_data(locale, calendar); data != nullptr) {
         auto const& formats = s_calendar_formats.at(data->date_time_formats);
-        return TRY(formats.to_unicode_calendar_format());
+        return formats.to_unicode_calendar_format();
     }
-    return OptionalNone {};
+    return {};
 }
 
-ErrorOr<Vector<CalendarPattern>> get_calendar_available_formats(StringView locale, StringView calendar)
+Vector<CalendarPattern> get_calendar_available_formats(StringView locale, StringView calendar)
 {
     Vector<CalendarPattern> result {};
 
     if (auto const* data = find_calendar_data(locale, calendar); data != nullptr) {
         auto const& available_formats = s_calendar_pattern_lists.at(data->available_formats);
-        TRY(result.try_ensure_capacity(available_formats.size()));
+        result.ensure_capacity(available_formats.size());
 
         for (auto const& format : available_formats)
-            result.unchecked_append(TRY(s_calendar_patterns[format].to_unicode_calendar_pattern()));
+            result.unchecked_append(s_calendar_patterns[format].to_unicode_calendar_pattern());
     }
 
     return result;
 }
 
-ErrorOr<Optional<CalendarRangePattern>> get_calendar_default_range_format(StringView locale, StringView calendar)
+Optional<CalendarRangePattern> get_calendar_default_range_format(StringView locale, StringView calendar)
 {
     if (auto const* data = find_calendar_data(locale, calendar); data != nullptr) {
         auto const& pattern = s_calendar_range_patterns[data->default_range_format];
-        return TRY(pattern.to_unicode_calendar_range_pattern());
+        return pattern.to_unicode_calendar_range_pattern();
     }
 
-    return OptionalNone {};
+    return {};
 }
 
-ErrorOr<Vector<CalendarRangePattern>> get_calendar_range_formats(StringView locale, StringView calendar, StringView skeleton)
+Vector<CalendarRangePattern> get_calendar_range_formats(StringView locale, StringView calendar, StringView skeleton)
 {
     Vector<CalendarRangePattern> result {};
 
@@ -2188,14 +2188,14 @@ ErrorOr<Vector<CalendarRangePattern>> get_calendar_range_formats(StringView loca
             auto const& pattern = s_calendar_range_patterns[format];
 
             if (skeleton == decode_string(pattern.skeleton))
-                TRY(result.try_append(TRY(pattern.to_unicode_calendar_range_pattern())));
+                result.append(pattern.to_unicode_calendar_range_pattern());
         }
     }
 
     return result;
 }
 
-ErrorOr<Vector<CalendarRangePattern>> get_calendar_range12_formats(StringView locale, StringView calendar, StringView skeleton)
+Vector<CalendarRangePattern> get_calendar_range12_formats(StringView locale, StringView calendar, StringView skeleton)
 {
     Vector<CalendarRangePattern> result {};
 
@@ -2206,14 +2206,14 @@ ErrorOr<Vector<CalendarRangePattern>> get_calendar_range12_formats(StringView lo
             auto const& pattern = s_calendar_range_patterns[format];
 
             if (skeleton == decode_string(pattern.skeleton))
-                TRY(result.try_append(TRY(pattern.to_unicode_calendar_range_pattern())));
+                result.append(pattern.to_unicode_calendar_range_pattern());
         }
     }
 
     return result;
 }
 
-static ErrorOr<ReadonlySpan<@string_index_type@>> find_calendar_symbols(StringView locale, StringView calendar, CalendarSymbol symbol, CalendarPatternStyle style)
+static ReadonlySpan<@string_index_type@> find_calendar_symbols(StringView locale, StringView calendar, CalendarSymbol symbol, CalendarPatternStyle style)
 {
     if (auto const* data = find_calendar_data(locale, calendar); data != nullptr) {
         auto const& symbols_list = s_calendar_symbol_lists[data->symbols];
@@ -2241,62 +2241,62 @@ static ErrorOr<ReadonlySpan<@string_index_type@>> find_calendar_symbols(StringVi
         return s_symbol_lists.at(symbol_list_index);
     }
 
-    return ReadonlySpan<@string_index_type@> {};
+    return {};
 }
 
-ErrorOr<Optional<StringView>> get_calendar_era_symbol(StringView locale, StringView calendar, CalendarPatternStyle style, Era value)
+Optional<StringView> get_calendar_era_symbol(StringView locale, StringView calendar, CalendarPatternStyle style, Era value)
 {
-    auto symbols = TRY(find_calendar_symbols(locale, calendar, CalendarSymbol::Era, style));
+    auto symbols = find_calendar_symbols(locale, calendar, CalendarSymbol::Era, style);
 
     if (auto value_index = to_underlying(value); value_index < symbols.size()) {
         if (auto symbol_index = symbols.at(value_index); symbol_index != 0)
-            return Optional<StringView> { decode_string(symbol_index) };
+            return decode_string(symbol_index);
     }
 
-    return OptionalNone {};
+    return {};
 }
 
-ErrorOr<Optional<StringView>> get_calendar_month_symbol(StringView locale, StringView calendar, CalendarPatternStyle style, Month value)
+Optional<StringView> get_calendar_month_symbol(StringView locale, StringView calendar, CalendarPatternStyle style, Month value)
 {
-    auto symbols = TRY(find_calendar_symbols(locale, calendar, CalendarSymbol::Month, style));
+    auto symbols = find_calendar_symbols(locale, calendar, CalendarSymbol::Month, style);
 
     if (auto value_index = to_underlying(value); value_index < symbols.size()) {
         if (auto symbol_index = symbols.at(value_index); symbol_index != 0)
-            return Optional<StringView> { decode_string(symbol_index) };
+            return decode_string(symbol_index);
     }
 
-    return OptionalNone {};
+    return {};
 }
 
-ErrorOr<Optional<StringView>> get_calendar_weekday_symbol(StringView locale, StringView calendar, CalendarPatternStyle style, Weekday value)
+Optional<StringView> get_calendar_weekday_symbol(StringView locale, StringView calendar, CalendarPatternStyle style, Weekday value)
 {
-    auto symbols = TRY(find_calendar_symbols(locale, calendar, CalendarSymbol::Weekday, style));
+    auto symbols = find_calendar_symbols(locale, calendar, CalendarSymbol::Weekday, style);
 
     if (auto value_index = to_underlying(value); value_index < symbols.size()) {
         if (auto symbol_index = symbols.at(value_index); symbol_index != 0)
-            return Optional<StringView> { decode_string(symbol_index) };
+            return decode_string(symbol_index);
     }
 
-    return OptionalNone {};
+    return {};
 }
 
-ErrorOr<Optional<StringView>> get_calendar_day_period_symbol(StringView locale, StringView calendar, CalendarPatternStyle style, DayPeriod value)
+Optional<StringView> get_calendar_day_period_symbol(StringView locale, StringView calendar, CalendarPatternStyle style, DayPeriod value)
 {
-    auto symbols = TRY(find_calendar_symbols(locale, calendar, CalendarSymbol::DayPeriod, style));
+    auto symbols = find_calendar_symbols(locale, calendar, CalendarSymbol::DayPeriod, style);
 
     if (auto value_index = to_underlying(value); value_index < symbols.size()) {
         if (auto symbol_index = symbols.at(value_index); symbol_index != 0)
-            return Optional<StringView> { decode_string(symbol_index) };
+            return decode_string(symbol_index);
     }
 
-    return OptionalNone {};
+    return {};
 }
 
-ErrorOr<Optional<StringView>> get_calendar_day_period_symbol_for_hour(StringView locale, StringView calendar, CalendarPatternStyle style, u8 hour)
+Optional<StringView> get_calendar_day_period_symbol_for_hour(StringView locale, StringView calendar, CalendarPatternStyle style, u8 hour)
 {
     auto locale_value = locale_from_string(locale);
     if (!locale_value.has_value())
-        return OptionalNone {};
+        return {};
 
     auto locale_index = to_underlying(*locale_value) - 1; // Subtract 1 because 0 == Locale::None.
 
diff --git a/Meta/Lagom/Tools/CodeGenerators/LibLocale/GenerateLocaleData.cpp b/Meta/Lagom/Tools/CodeGenerators/LibLocale/GenerateLocaleData.cpp
index 23495e31e60..4937170dc28 100644
--- a/Meta/Lagom/Tools/CodeGenerators/LibLocale/GenerateLocaleData.cpp
+++ b/Meta/Lagom/Tools/CodeGenerators/LibLocale/GenerateLocaleData.cpp
@@ -1680,7 +1680,7 @@ Optional<StringView> get_preferred_keyword_value_for_locale(StringView locale, S
     // FIXME: Calendar keywords are also region-based, and will need to be handled here when we support non-Gregorian calendars:
     //        https://github.com/unicode-org/cldr-json/blob/main/cldr-json/cldr-core/supplemental/calendarPreferenceData.json
     if (key == "hc"sv) {
-        auto hour_cycles = MUST(get_locale_hour_cycles(locale));
+        auto hour_cycles = get_locale_hour_cycles(locale);
         if (hour_cycles.is_empty())
             return OptionalNone {};
 
@@ -1709,7 +1709,7 @@ Vector<StringView> get_keywords_for_locale(StringView locale, StringView key)
     // FIXME: Calendar keywords are also region-based, and will need to be handled here when we support non-Gregorian calendars:
     //        https://github.com/unicode-org/cldr-json/blob/main/cldr-json/cldr-core/supplemental/calendarPreferenceData.json
     if (key == "hc"sv) {
-        auto hour_cycles = MUST(get_locale_hour_cycles(locale));
+        auto hour_cycles = get_locale_hour_cycles(locale);
 
         Vector<StringView> values;
         values.ensure_capacity(hour_cycles.size());
diff --git a/Tests/LibLocale/TestDateTimeFormat.cpp b/Tests/LibLocale/TestDateTimeFormat.cpp
index 62a8b7f5578..0941fdb4925 100644
--- a/Tests/LibLocale/TestDateTimeFormat.cpp
+++ b/Tests/LibLocale/TestDateTimeFormat.cpp
@@ -75,7 +75,7 @@ TEST_CASE(time_zone_name)
     constexpr auto jan_1_2022 = AK::UnixDateTime::from_seconds_since_epoch(1640995200); // Saturday, January 1, 2022 12:00:00 AM
 
     for (auto const& test : test_data) {
-        auto time_zone = MUST(Locale::format_time_zone(test.locale, test.time_zone, test.style, jan_1_2022));
+        auto time_zone = Locale::format_time_zone(test.locale, test.time_zone, test.style, jan_1_2022);
         EXPECT_EQ(time_zone, test.expected_result);
     }
 }
@@ -125,7 +125,7 @@ TEST_CASE(time_zone_name_dst)
     constexpr auto sep_19_2022 = AK::UnixDateTime::from_seconds_since_epoch(1663553728); // Monday, September 19, 2022 2:15:28 AM
 
     for (auto const& test : test_data) {
-        auto time_zone = MUST(Locale::format_time_zone(test.locale, test.time_zone, test.style, sep_19_2022));
+        auto time_zone = Locale::format_time_zone(test.locale, test.time_zone, test.style, sep_19_2022);
         EXPECT_EQ(time_zone, test.expected_result);
     }
 }
@@ -182,7 +182,7 @@ TEST_CASE(format_time_zone_offset)
     };
 
     for (auto const& test : test_data) {
-        auto time_zone = MUST(Locale::format_time_zone(test.locale, test.time_zone, test.style, test.time));
+        auto time_zone = Locale::format_time_zone(test.locale, test.time_zone, test.style, test.time);
         EXPECT_EQ(time_zone, test.expected_result);
     }
 }
diff --git a/Userland/Applications/ClockSettings/TimeZoneSettingsWidget.cpp b/Userland/Applications/ClockSettings/TimeZoneSettingsWidget.cpp
index 6e18da766ff..4cffade8c34 100644
--- a/Userland/Applications/ClockSettings/TimeZoneSettingsWidget.cpp
+++ b/Userland/Applications/ClockSettings/TimeZoneSettingsWidget.cpp
@@ -135,8 +135,8 @@ void TimeZoneSettingsWidget::set_time_zone_location()
     auto locale = Locale::default_locale();
     auto now = AK::UnixDateTime::now();
 
-    auto name = Locale::format_time_zone(locale, m_time_zone, Locale::CalendarPatternStyle::Long, now).release_value_but_fixme_should_propagate_errors();
-    auto offset = Locale::format_time_zone(locale, m_time_zone, Locale::CalendarPatternStyle::LongOffset, now).release_value_but_fixme_should_propagate_errors();
+    auto name = Locale::format_time_zone(locale, m_time_zone, Locale::CalendarPatternStyle::Long, now);
+    auto offset = Locale::format_time_zone(locale, m_time_zone, Locale::CalendarPatternStyle::LongOffset, now);
 
     m_time_zone_text = DeprecatedString::formatted("{}\n({})", name, offset);
 }
diff --git a/Userland/Libraries/LibJS/Runtime/Intl/DateTimeFormat.cpp b/Userland/Libraries/LibJS/Runtime/Intl/DateTimeFormat.cpp
index 99a1cd91fe4..4a2e8aaddb5 100644
--- a/Userland/Libraries/LibJS/Runtime/Intl/DateTimeFormat.cpp
+++ b/Userland/Libraries/LibJS/Runtime/Intl/DateTimeFormat.cpp
@@ -73,8 +73,8 @@ ThrowCompletionOr<Optional<::Locale::CalendarPattern>> date_time_style_format(VM
     ::Locale::CalendarPattern time_format {};
     ::Locale::CalendarPattern date_format {};
 
-    auto get_pattern = [&](auto type, auto style) -> ThrowCompletionOr<Optional<::Locale::CalendarPattern>> {
-        auto formats = TRY_OR_THROW_OOM(vm, ::Locale::get_calendar_format(data_locale, date_time_format.calendar(), type));
+    auto get_pattern = [&](auto type, auto style) -> Optional<::Locale::CalendarPattern> {
+        auto formats = ::Locale::get_calendar_format(data_locale, date_time_format.calendar(), type);
 
         if (formats.has_value()) {
             switch (style) {
@@ -89,14 +89,14 @@ ThrowCompletionOr<Optional<::Locale::CalendarPattern>> date_time_style_format(VM
             }
         }
 
-        return OptionalNone {};
+        return {};
     };
 
     // 1. If timeStyle is not undefined, then
     if (date_time_format.has_time_style()) {
         // a. Assert: timeStyle is one of "full", "long", "medium", or "short".
         // b. Let timeFormat be styles.[[TimeFormat]].[[<timeStyle>]].
-        auto pattern = MUST_OR_THROW_OOM(get_pattern(::Locale::CalendarFormatType::Time, date_time_format.time_style()));
+        auto pattern = get_pattern(::Locale::CalendarFormatType::Time, date_time_format.time_style());
         if (!pattern.has_value())
             return OptionalNone {};
 
@@ -107,7 +107,7 @@ ThrowCompletionOr<Optional<::Locale::CalendarPattern>> date_time_style_format(VM
     if (date_time_format.has_date_style()) {
         // a. Assert: dateStyle is one of "full", "long", "medium", or "short".
         // b. Let dateFormat be styles.[[DateFormat]].[[<dateStyle>]].
-        auto pattern = MUST_OR_THROW_OOM(get_pattern(::Locale::CalendarFormatType::Date, date_time_format.date_style()));
+        auto pattern = get_pattern(::Locale::CalendarFormatType::Date, date_time_format.date_style());
         if (!pattern.has_value())
             return OptionalNone {};
 
@@ -131,7 +131,7 @@ ThrowCompletionOr<Optional<::Locale::CalendarPattern>> date_time_style_format(VM
         });
 
         // d. Let connector be styles.[[DateTimeFormat]].[[<dateStyle>]].
-        auto connector = MUST_OR_THROW_OOM(get_pattern(::Locale::CalendarFormatType::DateTime, date_time_format.date_style()));
+        auto connector = get_pattern(::Locale::CalendarFormatType::DateTime, date_time_format.date_style());
         if (!connector.has_value())
             return OptionalNone {};
 
@@ -155,7 +155,7 @@ ThrowCompletionOr<Optional<::Locale::CalendarPattern>> date_time_style_format(VM
         // NOTE: Our implementation of steps h-j differ from the spec. LibUnicode does not attach range patterns to the
         //       format pattern; rather, lookups for range patterns are performed separately based on the format pattern's
         //       skeleton. So we form a new skeleton here and defer the range pattern lookups.
-        format.skeleton = TRY_OR_THROW_OOM(vm, ::Locale::combine_skeletons(date_format.skeleton, time_format.skeleton));
+        format.skeleton = ::Locale::combine_skeletons(date_format.skeleton, time_format.skeleton);
 
         // k. Return format.
         return format;
@@ -424,7 +424,7 @@ static Optional<StyleAndValue> find_calendar_field(StringView name, ::Locale::Ca
     return {};
 }
 
-static ThrowCompletionOr<Optional<StringView>> resolve_day_period(VM& vm, StringView locale, StringView calendar, ::Locale::CalendarPatternStyle style, ReadonlySpan<PatternPartition> pattern_parts, LocalTime local_time)
+static Optional<StringView> resolve_day_period(StringView locale, StringView calendar, ::Locale::CalendarPatternStyle style, ReadonlySpan<PatternPartition> pattern_parts, LocalTime local_time)
 {
     // Use the "noon" day period if the locale has it, but only if the time is either exactly 12:00.00 or would be displayed as such.
     if (local_time.hour == 12) {
@@ -439,13 +439,13 @@ static ThrowCompletionOr<Optional<StringView>> resolve_day_period(VM& vm, String
         });
 
         if (it == pattern_parts.end()) {
-            auto noon_symbol = TRY_OR_THROW_OOM(vm, ::Locale::get_calendar_day_period_symbol(locale, calendar, style, ::Locale::DayPeriod::Noon));
+            auto noon_symbol = ::Locale::get_calendar_day_period_symbol(locale, calendar, style, ::Locale::DayPeriod::Noon);
             if (noon_symbol.has_value())
                 return *noon_symbol;
         }
     }
 
-    return TRY_OR_THROW_OOM(vm, ::Locale::get_calendar_day_period_symbol_for_hour(locale, calendar, style, local_time.hour));
+    return ::Locale::get_calendar_day_period_symbol_for_hour(locale, calendar, style, local_time.hour);
 }
 
 // 11.5.5 FormatDateTimePattern ( dateTimeFormat, patternParts, x, rangeFormatOptions ), https://tc39.es/ecma402/#sec-formatdatetimepattern
@@ -552,7 +552,7 @@ ThrowCompletionOr<Vector<PatternPartition>> format_date_time_pattern(VM& vm, Dat
             auto style = date_time_format.day_period();
 
             // ii. Let fv be a String value representing the day period of tm in the form given by f; the String value depends upon the implementation and the effective locale of dateTimeFormat.
-            auto symbol = MUST_OR_THROW_OOM(resolve_day_period(vm, data_locale, date_time_format.calendar(), style, pattern_parts, local_time));
+            auto symbol = resolve_day_period(data_locale, date_time_format.calendar(), style, pattern_parts, local_time);
             if (symbol.has_value())
                 formatted_value = TRY_OR_THROW_OOM(vm, String::from_utf8(*symbol));
 
@@ -571,7 +571,7 @@ ThrowCompletionOr<Vector<PatternPartition>> format_date_time_pattern(VM& vm, Dat
             // iii. Let fv be a String value representing v in the form given by f; the String value depends upon the implementation and the effective locale of dateTimeFormat.
             //      The String value may also depend on the value of the [[InDST]] field of tm if f is "short", "long", "shortOffset", or "longOffset".
             //      If the implementation does not have a localized representation of f, then use the String value of v itself.
-            auto formatted_value = TRY_OR_THROW_OOM(vm, ::Locale::format_time_zone(data_locale, value, style, local_time.time_since_epoch()));
+            auto formatted_value = ::Locale::format_time_zone(data_locale, value, style, local_time.time_since_epoch());
 
             // iv. Append a new Record { [[Type]]: p, [[Value]]: fv } as the last element of the list result.
             TRY_OR_THROW_OOM(vm, result.try_append({ "timeZoneName"sv, move(formatted_value) }));
@@ -652,11 +652,11 @@ ThrowCompletionOr<Vector<PatternPartition>> format_date_time_pattern(VM& vm, Dat
                 Optional<StringView> symbol;
 
                 if (part == "era"sv)
-                    symbol = TRY_OR_THROW_OOM(vm, ::Locale::get_calendar_era_symbol(data_locale, date_time_format.calendar(), style, static_cast<::Locale::Era>(value)));
+                    symbol = ::Locale::get_calendar_era_symbol(data_locale, date_time_format.calendar(), style, static_cast<::Locale::Era>(value));
                 else if (part == "month"sv)
-                    symbol = TRY_OR_THROW_OOM(vm, ::Locale::get_calendar_month_symbol(data_locale, date_time_format.calendar(), style, static_cast<::Locale::Month>(value - 1)));
+                    symbol = ::Locale::get_calendar_month_symbol(data_locale, date_time_format.calendar(), style, static_cast<::Locale::Month>(value - 1));
                 else if (part == "weekday"sv)
-                    symbol = TRY_OR_THROW_OOM(vm, ::Locale::get_calendar_weekday_symbol(data_locale, date_time_format.calendar(), style, static_cast<::Locale::Weekday>(value)));
+                    symbol = ::Locale::get_calendar_weekday_symbol(data_locale, date_time_format.calendar(), style, static_cast<::Locale::Weekday>(value));
 
                 if (symbol.has_value())
                     formatted_value = TRY_OR_THROW_OOM(vm, String::from_utf8(*symbol));
@@ -684,13 +684,13 @@ ThrowCompletionOr<Vector<PatternPartition>> format_date_time_pattern(VM& vm, Dat
             // ii. If v is greater than 11, then
             if (value > 11) {
                 // 1. Let fv be an implementation and locale dependent String value representing "post meridiem".
-                auto symbol = TRY_OR_THROW_OOM(vm, ::Locale::get_calendar_day_period_symbol(data_locale, date_time_format.calendar(), ::Locale::CalendarPatternStyle::Short, ::Locale::DayPeriod::PM));
+                auto symbol = ::Locale::get_calendar_day_period_symbol(data_locale, date_time_format.calendar(), ::Locale::CalendarPatternStyle::Short, ::Locale::DayPeriod::PM);
                 formatted_value = TRY_OR_THROW_OOM(vm, String::from_utf8(symbol.value_or("PM"sv)));
             }
             // iii. Else,
             else {
                 // 1. Let fv be an implementation and locale dependent String value representing "ante meridiem".
-                auto symbol = TRY_OR_THROW_OOM(vm, ::Locale::get_calendar_day_period_symbol(data_locale, date_time_format.calendar(), ::Locale::CalendarPatternStyle::Short, ::Locale::DayPeriod::AM));
+                auto symbol = ::Locale::get_calendar_day_period_symbol(data_locale, date_time_format.calendar(), ::Locale::CalendarPatternStyle::Short, ::Locale::DayPeriod::AM);
                 formatted_value = TRY_OR_THROW_OOM(vm, String::from_utf8(symbol.value_or("AM"sv)));
             }
 
@@ -806,30 +806,29 @@ ThrowCompletionOr<Array*> format_date_time_to_parts(VM& vm, DateTimeFormat& date
 }
 
 template<typename Callback>
-ThrowCompletionOr<void> for_each_range_pattern_field(LocalTime const& time1, LocalTime const& time2, Callback&& callback)
+void for_each_range_pattern_field(LocalTime const& time1, LocalTime const& time2, Callback&& callback)
 {
     // Table 4: Range pattern fields, https://tc39.es/ecma402/#table-datetimeformat-rangepatternfields
-    if (TRY(callback(static_cast<u8>(time1.era), static_cast<u8>(time2.era), ::Locale::CalendarRangePattern::Field::Era)) == IterationDecision::Break)
-        return {};
-    if (TRY(callback(time1.year, time2.year, ::Locale::CalendarRangePattern::Field::Year)) == IterationDecision::Break)
-        return {};
-    if (TRY(callback(time1.month, time2.month, ::Locale::CalendarRangePattern::Field::Month)) == IterationDecision::Break)
-        return {};
-    if (TRY(callback(time1.day, time2.day, ::Locale::CalendarRangePattern::Field::Day)) == IterationDecision::Break)
-        return {};
-    if (TRY(callback(time1.hour, time2.hour, ::Locale::CalendarRangePattern::Field::AmPm)) == IterationDecision::Break)
-        return {};
-    if (TRY(callback(time1.hour, time2.hour, ::Locale::CalendarRangePattern::Field::DayPeriod)) == IterationDecision::Break)
-        return {};
-    if (TRY(callback(time1.hour, time2.hour, ::Locale::CalendarRangePattern::Field::Hour)) == IterationDecision::Break)
-        return {};
-    if (TRY(callback(time1.minute, time2.minute, ::Locale::CalendarRangePattern::Field::Minute)) == IterationDecision::Break)
-        return {};
-    if (TRY(callback(time1.second, time2.second, ::Locale::CalendarRangePattern::Field::Second)) == IterationDecision::Break)
-        return {};
-    if (TRY(callback(time1.millisecond, time2.millisecond, ::Locale::CalendarRangePattern::Field::FractionalSecondDigits)) == IterationDecision::Break)
-        return {};
-    return {};
+    if (callback(static_cast<u8>(time1.era), static_cast<u8>(time2.era), ::Locale::CalendarRangePattern::Field::Era) == IterationDecision::Break)
+        return;
+    if (callback(time1.year, time2.year, ::Locale::CalendarRangePattern::Field::Year) == IterationDecision::Break)
+        return;
+    if (callback(time1.month, time2.month, ::Locale::CalendarRangePattern::Field::Month) == IterationDecision::Break)
+        return;
+    if (callback(time1.day, time2.day, ::Locale::CalendarRangePattern::Field::Day) == IterationDecision::Break)
+        return;
+    if (callback(time1.hour, time2.hour, ::Locale::CalendarRangePattern::Field::AmPm) == IterationDecision::Break)
+        return;
+    if (callback(time1.hour, time2.hour, ::Locale::CalendarRangePattern::Field::DayPeriod) == IterationDecision::Break)
+        return;
+    if (callback(time1.hour, time2.hour, ::Locale::CalendarRangePattern::Field::Hour) == IterationDecision::Break)
+        return;
+    if (callback(time1.minute, time2.minute, ::Locale::CalendarRangePattern::Field::Minute) == IterationDecision::Break)
+        return;
+    if (callback(time1.second, time2.second, ::Locale::CalendarRangePattern::Field::Second) == IterationDecision::Break)
+        return;
+    if (callback(time1.millisecond, time2.millisecond, ::Locale::CalendarRangePattern::Field::FractionalSecondDigits) == IterationDecision::Break)
+        return;
 }
 
 template<typename Callback>
@@ -879,7 +878,7 @@ ThrowCompletionOr<Vector<PatternPartitionWithSource>> partition_date_time_range_
     bool pattern_contains_larger_date_field = false;
 
     // 11. While dateFieldsPracticallyEqual is true and patternContainsLargerDateField is false, repeat for each row of Table 4 in order, except the header row:
-    TRY(for_each_range_pattern_field(start_local_time, end_local_time, [&](auto start_value, auto end_value, auto field_name) -> ThrowCompletionOr<IterationDecision> {
+    for_each_range_pattern_field(start_local_time, end_local_time, [&](auto start_value, auto end_value, auto field_name) {
         // a. Let fieldName be the name given in the Range Pattern Field column of the row.
 
         // b. If rangePatterns has a field [[<fieldName>]], let rp be rangePatterns.[[<fieldName>]]; else let rp be undefined.
@@ -918,10 +917,10 @@ ThrowCompletionOr<Vector<PatternPartitionWithSource>> partition_date_time_range_
             // iii. Else if fieldName is equal to [[DayPeriod]], then
             case ::Locale::CalendarRangePattern::Field::DayPeriod: {
                 // 1. Let v1 be a String value representing the day period of tm1; the String value depends upon the implementation and the effective locale of dateTimeFormat.
-                auto start_period = TRY_OR_THROW_OOM(vm, ::Locale::get_calendar_day_period_symbol_for_hour(date_time_format.data_locale(), date_time_format.calendar(), ::Locale::CalendarPatternStyle::Short, start_value));
+                auto start_period = ::Locale::get_calendar_day_period_symbol_for_hour(date_time_format.data_locale(), date_time_format.calendar(), ::Locale::CalendarPatternStyle::Short, start_value);
 
                 // 2. Let v2 be a String value representing the day period of tm2; the String value depends upon the implementation and the effective locale of dateTimeFormat.
-                auto end_period = TRY_OR_THROW_OOM(vm, ::Locale::get_calendar_day_period_symbol_for_hour(date_time_format.data_locale(), date_time_format.calendar(), ::Locale::CalendarPatternStyle::Short, end_value));
+                auto end_period = ::Locale::get_calendar_day_period_symbol_for_hour(date_time_format.data_locale(), date_time_format.calendar(), ::Locale::CalendarPatternStyle::Short, end_value);
 
                 // 3. If v1 is not equal to v2, then
                 if (start_period != end_period) {
@@ -981,7 +980,7 @@ ThrowCompletionOr<Vector<PatternPartitionWithSource>> partition_date_time_range_
         if (date_fields_practically_equal && !pattern_contains_larger_date_field)
             return IterationDecision::Continue;
         return IterationDecision::Break;
-    }));
+    });
 
     // 12. If dateFieldsPracticallyEqual is true, then
     if (date_fields_practically_equal) {
@@ -1011,7 +1010,7 @@ ThrowCompletionOr<Vector<PatternPartitionWithSource>> partition_date_time_range_
     // 14. If rangePattern is undefined, then
     if (!range_pattern.has_value()) {
         // a. Let rangePattern be rangePatterns.[[Default]].
-        range_pattern = TRY_OR_THROW_OOM(vm, ::Locale::get_calendar_default_range_format(date_time_format.data_locale(), date_time_format.calendar()));
+        range_pattern = ::Locale::get_calendar_default_range_format(date_time_format.data_locale(), date_time_format.calendar());
 
         // Non-standard, range_pattern will be empty if Unicode data generation is disabled.
         if (!range_pattern.has_value())
diff --git a/Userland/Libraries/LibJS/Runtime/Intl/DateTimeFormatConstructor.cpp b/Userland/Libraries/LibJS/Runtime/Intl/DateTimeFormatConstructor.cpp
index bcc6b0d7dc8..ce2f3ad2c8a 100644
--- a/Userland/Libraries/LibJS/Runtime/Intl/DateTimeFormatConstructor.cpp
+++ b/Userland/Libraries/LibJS/Runtime/Intl/DateTimeFormatConstructor.cpp
@@ -166,7 +166,7 @@ ThrowCompletionOr<NonnullGCPtr<DateTimeFormat>> create_date_time_format(VM& vm,
 
     // 24. Let dataLocaleData be localeData.[[<dataLocale>]].
     // 25. Let hcDefault be dataLocaleData.[[hourCycle]].
-    auto default_hour_cycle = TRY_OR_THROW_OOM(vm, ::Locale::get_default_regional_hour_cycle(data_locale));
+    auto default_hour_cycle = ::Locale::get_default_regional_hour_cycle(data_locale);
 
     // Non-standard, default_hour_cycle will be empty if Unicode data generation is disabled.
     if (!default_hour_cycle.has_value()) {
@@ -394,7 +394,7 @@ ThrowCompletionOr<NonnullGCPtr<DateTimeFormat>> create_date_time_format(VM& vm,
         }
 
         // f. Let formats be dataLocaleData.[[formats]].[[<resolvedCalendar>]].
-        auto formats = TRY_OR_THROW_OOM(vm, ::Locale::get_calendar_available_formats(data_locale, date_time_format->calendar()));
+        auto formats = ::Locale::get_calendar_available_formats(data_locale, date_time_format->calendar());
 
         // g. If matcher is "basic", then
         if (matcher.as_string().utf8_string_view() == "basic"sv) {
@@ -440,7 +440,7 @@ ThrowCompletionOr<NonnullGCPtr<DateTimeFormat>> create_date_time_format(VM& vm,
         }
 
         // b. Let rangePatterns be bestFormat.[[rangePatterns12]].
-        range_patterns = TRY_OR_THROW_OOM(vm, ::Locale::get_calendar_range12_formats(data_locale, date_time_format->calendar(), best_format->skeleton));
+        range_patterns = ::Locale::get_calendar_range12_formats(data_locale, date_time_format->calendar(), best_format->skeleton);
     }
     // 48. Else,
     else {
@@ -448,7 +448,7 @@ ThrowCompletionOr<NonnullGCPtr<DateTimeFormat>> create_date_time_format(VM& vm,
         pattern = move(best_format->pattern);
 
         // b. Let rangePatterns be bestFormat.[[rangePatterns]].
-        range_patterns = TRY_OR_THROW_OOM(vm, ::Locale::get_calendar_range_formats(data_locale, date_time_format->calendar(), best_format->skeleton));
+        range_patterns = ::Locale::get_calendar_range_formats(data_locale, date_time_format->calendar(), best_format->skeleton);
     }
 
     // 49. Set dateTimeFormat.[[Pattern]] to pattern.
diff --git a/Userland/Libraries/LibJS/Runtime/Intl/Locale.cpp b/Userland/Libraries/LibJS/Runtime/Intl/Locale.cpp
index 682bc53633a..cd74aabc0ca 100644
--- a/Userland/Libraries/LibJS/Runtime/Intl/Locale.cpp
+++ b/Userland/Libraries/LibJS/Runtime/Intl/Locale.cpp
@@ -208,8 +208,8 @@ static u8 weekday_to_integer(Optional<::Locale::Weekday> weekday, ::Locale::Week
 
 static ThrowCompletionOr<Vector<u8>> weekend_of_locale(VM& vm, StringView locale)
 {
-    auto weekend_start = weekday_to_integer(TRY_OR_THROW_OOM(vm, ::Locale::get_locale_weekend_start(locale)), ::Locale::Weekday::Saturday);
-    auto weekend_end = weekday_to_integer(TRY_OR_THROW_OOM(vm, ::Locale::get_locale_weekend_end(locale)), ::Locale::Weekday::Sunday);
+    auto weekend_start = weekday_to_integer(::Locale::get_locale_weekend_start(locale), ::Locale::Weekday::Saturday);
+    auto weekend_end = weekday_to_integer(::Locale::get_locale_weekend_end(locale), ::Locale::Weekday::Sunday);
 
     // There currently aren't any regions in the CLDR which wrap around from Sunday (7) to Monday (1).
     // If this changes, this logic will need to be updated to handle that.
@@ -235,8 +235,8 @@ ThrowCompletionOr<WeekInfo> week_info_of_locale(VM& vm, Locale const& locale_obj
 
     // 3. Return a record whose fields are defined by Table 1, with values based on locale.
     WeekInfo week_info {};
-    week_info.minimal_days = TRY_OR_THROW_OOM(vm, ::Locale::get_locale_minimum_days(locale)).value_or(1);
-    week_info.first_day = weekday_to_integer(TRY_OR_THROW_OOM(vm, ::Locale::get_locale_first_day(locale)), ::Locale::Weekday::Monday);
+    week_info.minimal_days = ::Locale::get_locale_minimum_days(locale).value_or(1);
+    week_info.first_day = weekday_to_integer(::Locale::get_locale_first_day(locale), ::Locale::Weekday::Monday);
     week_info.weekend = MUST_OR_THROW_OOM(weekend_of_locale(vm, locale));
 
     return week_info;
diff --git a/Userland/Libraries/LibLocale/DateTimeFormat.cpp b/Userland/Libraries/LibLocale/DateTimeFormat.cpp
index fa128b321e2..4a8d78fe801 100644
--- a/Userland/Libraries/LibLocale/DateTimeFormat.cpp
+++ b/Userland/Libraries/LibLocale/DateTimeFormat.cpp
@@ -92,10 +92,10 @@ StringView calendar_pattern_style_to_string(CalendarPatternStyle style)
 }
 
 Optional<HourCycleRegion> __attribute__((weak)) hour_cycle_region_from_string(StringView) { return {}; }
-ErrorOr<Vector<HourCycle>> __attribute__((weak)) get_regional_hour_cycles(StringView) { return Vector<HourCycle> {}; }
+Vector<HourCycle> __attribute__((weak)) get_regional_hour_cycles(StringView) { return {}; }
 
-template<typename T, FallibleFunction<StringView> GetRegionalValues>
-static ErrorOr<T> find_regional_values_for_locale(StringView locale, GetRegionalValues&& get_regional_values)
+template<typename T, typename GetRegionalValues>
+static T find_regional_values_for_locale(StringView locale, GetRegionalValues&& get_regional_values)
 {
     auto has_value = [](auto const& container) {
         if constexpr (requires { container.has_value(); })
@@ -104,7 +104,7 @@ static ErrorOr<T> find_regional_values_for_locale(StringView locale, GetRegional
             return !container.is_empty();
     };
 
-    if (auto regional_values = TRY(get_regional_values(locale)); has_value(regional_values))
+    if (auto regional_values = get_regional_values(locale); has_value(regional_values))
         return regional_values;
 
     auto return_default_values = [&]() { return get_regional_values("001"sv); };
@@ -118,35 +118,29 @@ static ErrorOr<T> find_regional_values_for_locale(StringView locale, GetRegional
     if (!language.has_value() || !language->region.has_value())
         return return_default_values();
 
-    if (auto regional_values = TRY(get_regional_values(*language->region)); has_value(regional_values))
+    if (auto regional_values = get_regional_values(*language->region); has_value(regional_values))
         return regional_values;
 
     return return_default_values();
 }
 
-template<typename T, typename GetRegionalValues>
-static ErrorOr<T> find_regional_values_for_locale(StringView locale, GetRegionalValues&& get_regional_values)
-{
-    return find_regional_values_for_locale<T>(locale, [&](auto region) -> ErrorOr<T> { return get_regional_values(region); });
-}
-
 // https://unicode.org/reports/tr35/tr35-dates.html#Date_Field_Symbol_Table
-ErrorOr<Vector<HourCycle>> get_locale_hour_cycles(StringView locale)
+Vector<HourCycle> get_locale_hour_cycles(StringView locale)
 {
     return find_regional_values_for_locale<Vector<HourCycle>>(locale, get_regional_hour_cycles);
 }
 
-ErrorOr<Optional<HourCycle>> get_default_regional_hour_cycle(StringView locale)
+Optional<HourCycle> get_default_regional_hour_cycle(StringView locale)
 {
-    if (auto hour_cycles = TRY(get_locale_hour_cycles(locale)); !hour_cycles.is_empty())
+    if (auto hour_cycles = get_locale_hour_cycles(locale); !hour_cycles.is_empty())
         return hour_cycles.first();
-    return OptionalNone {};
+    return {};
 }
 
 Optional<MinimumDaysRegion> __attribute__((weak)) minimum_days_region_from_string(StringView) { return {}; }
 Optional<u8> __attribute__((weak)) get_regional_minimum_days(StringView) { return {}; }
 
-ErrorOr<Optional<u8>> get_locale_minimum_days(StringView locale)
+Optional<u8> get_locale_minimum_days(StringView locale)
 {
     return find_regional_values_for_locale<Optional<u8>>(locale, get_regional_minimum_days);
 }
@@ -154,7 +148,7 @@ ErrorOr<Optional<u8>> get_locale_minimum_days(StringView locale)
 Optional<FirstDayRegion> __attribute__((weak)) first_day_region_from_string(StringView) { return {}; }
 Optional<Weekday> __attribute__((weak)) get_regional_first_day(StringView) { return {}; }
 
-ErrorOr<Optional<Weekday>> get_locale_first_day(StringView locale)
+Optional<Weekday> get_locale_first_day(StringView locale)
 {
     return find_regional_values_for_locale<Optional<Weekday>>(locale, get_regional_first_day);
 }
@@ -162,7 +156,7 @@ ErrorOr<Optional<Weekday>> get_locale_first_day(StringView locale)
 Optional<WeekendStartRegion> __attribute__((weak)) weekend_start_region_from_string(StringView) { return {}; }
 Optional<Weekday> __attribute__((weak)) get_regional_weekend_start(StringView) { return {}; }
 
-ErrorOr<Optional<Weekday>> get_locale_weekend_start(StringView locale)
+Optional<Weekday> get_locale_weekend_start(StringView locale)
 {
     return find_regional_values_for_locale<Optional<Weekday>>(locale, get_regional_weekend_start);
 }
@@ -170,12 +164,12 @@ ErrorOr<Optional<Weekday>> get_locale_weekend_start(StringView locale)
 Optional<WeekendEndRegion> __attribute__((weak)) weekend_end_region_from_string(StringView) { return {}; }
 Optional<Weekday> __attribute__((weak)) get_regional_weekend_end(StringView) { return {}; }
 
-ErrorOr<Optional<Weekday>> get_locale_weekend_end(StringView locale)
+Optional<Weekday> get_locale_weekend_end(StringView locale)
 {
     return find_regional_values_for_locale<Optional<Weekday>>(locale, get_regional_weekend_end);
 }
 
-ErrorOr<String> combine_skeletons(StringView first, StringView second)
+String combine_skeletons(StringView first, StringView second)
 {
     // https://unicode.org/reports/tr35/tr35-dates.html#availableFormats_appendItems
     constexpr auto field_order = Array {
@@ -193,34 +187,34 @@ ErrorOr<String> combine_skeletons(StringView first, StringView second)
 
     StringBuilder builder;
 
-    auto append_from_skeleton = [&](auto skeleton, auto ch) -> ErrorOr<bool> {
+    auto append_from_skeleton = [&](auto skeleton, auto ch) {
         auto first_index = skeleton.find(ch);
         if (!first_index.has_value())
             return false;
 
         auto last_index = skeleton.find_last(ch);
 
-        TRY(builder.try_append(skeleton.substring_view(*first_index, *last_index - *first_index + 1)));
+        builder.append(skeleton.substring_view(*first_index, *last_index - *first_index + 1));
         return true;
     };
 
     for (auto fields : field_order) {
         for (auto ch : fields) {
-            if (TRY(append_from_skeleton(first, ch)))
+            if (append_from_skeleton(first, ch))
                 break;
-            if (TRY(append_from_skeleton(second, ch)))
+            if (append_from_skeleton(second, ch))
                 break;
         }
     }
 
-    return builder.to_string();
+    return MUST(builder.to_string());
 }
 
-ErrorOr<Optional<CalendarFormat>> __attribute__((weak)) get_calendar_date_format(StringView, StringView) { return OptionalNone {}; }
-ErrorOr<Optional<CalendarFormat>> __attribute__((weak)) get_calendar_time_format(StringView, StringView) { return OptionalNone {}; }
-ErrorOr<Optional<CalendarFormat>> __attribute__((weak)) get_calendar_date_time_format(StringView, StringView) { return OptionalNone {}; }
+Optional<CalendarFormat> __attribute__((weak)) get_calendar_date_format(StringView, StringView) { return {}; }
+Optional<CalendarFormat> __attribute__((weak)) get_calendar_time_format(StringView, StringView) { return {}; }
+Optional<CalendarFormat> __attribute__((weak)) get_calendar_date_time_format(StringView, StringView) { return {}; }
 
-ErrorOr<Optional<CalendarFormat>> get_calendar_format(StringView locale, StringView calendar, CalendarFormatType type)
+Optional<CalendarFormat> get_calendar_format(StringView locale, StringView calendar, CalendarFormatType type)
 {
     switch (type) {
     case CalendarFormatType::Date:
@@ -234,31 +228,31 @@ ErrorOr<Optional<CalendarFormat>> get_calendar_format(StringView locale, StringV
     }
 }
 
-ErrorOr<Vector<CalendarPattern>> __attribute__((weak)) get_calendar_available_formats(StringView, StringView) { return Vector<CalendarPattern> {}; }
-ErrorOr<Optional<CalendarRangePattern>> __attribute__((weak)) get_calendar_default_range_format(StringView, StringView) { return OptionalNone {}; }
-ErrorOr<Vector<CalendarRangePattern>> __attribute__((weak)) get_calendar_range_formats(StringView, StringView, StringView) { return Vector<CalendarRangePattern> {}; }
-ErrorOr<Vector<CalendarRangePattern>> __attribute__((weak)) get_calendar_range12_formats(StringView, StringView, StringView) { return Vector<CalendarRangePattern> {}; }
-ErrorOr<Optional<StringView>> __attribute__((weak)) get_calendar_era_symbol(StringView, StringView, CalendarPatternStyle, Era) { return OptionalNone {}; }
-ErrorOr<Optional<StringView>> __attribute__((weak)) get_calendar_month_symbol(StringView, StringView, CalendarPatternStyle, Month) { return OptionalNone {}; }
-ErrorOr<Optional<StringView>> __attribute__((weak)) get_calendar_weekday_symbol(StringView, StringView, CalendarPatternStyle, Weekday) { return OptionalNone {}; }
-ErrorOr<Optional<StringView>> __attribute__((weak)) get_calendar_day_period_symbol(StringView, StringView, CalendarPatternStyle, DayPeriod) { return OptionalNone {}; }
-ErrorOr<Optional<StringView>> __attribute__((weak)) get_calendar_day_period_symbol_for_hour(StringView, StringView, CalendarPatternStyle, u8) { return OptionalNone {}; }
+Vector<CalendarPattern> __attribute__((weak)) get_calendar_available_formats(StringView, StringView) { return {}; }
+Optional<CalendarRangePattern> __attribute__((weak)) get_calendar_default_range_format(StringView, StringView) { return {}; }
+Vector<CalendarRangePattern> __attribute__((weak)) get_calendar_range_formats(StringView, StringView, StringView) { return {}; }
+Vector<CalendarRangePattern> __attribute__((weak)) get_calendar_range12_formats(StringView, StringView, StringView) { return {}; }
+Optional<StringView> __attribute__((weak)) get_calendar_era_symbol(StringView, StringView, CalendarPatternStyle, Era) { return {}; }
+Optional<StringView> __attribute__((weak)) get_calendar_month_symbol(StringView, StringView, CalendarPatternStyle, Month) { return {}; }
+Optional<StringView> __attribute__((weak)) get_calendar_weekday_symbol(StringView, StringView, CalendarPatternStyle, Weekday) { return {}; }
+Optional<StringView> __attribute__((weak)) get_calendar_day_period_symbol(StringView, StringView, CalendarPatternStyle, DayPeriod) { return {}; }
+Optional<StringView> __attribute__((weak)) get_calendar_day_period_symbol_for_hour(StringView, StringView, CalendarPatternStyle, u8) { return {}; }
 
 Optional<StringView> __attribute__((weak)) get_time_zone_name(StringView, StringView, CalendarPatternStyle, TimeZone::InDST) { return {}; }
 Optional<TimeZoneFormat> __attribute__((weak)) get_time_zone_format(StringView) { return {}; }
 
-static ErrorOr<Optional<String>> format_time_zone_offset(StringView locale, CalendarPatternStyle style, i64 offset_seconds)
+static Optional<String> format_time_zone_offset(StringView locale, CalendarPatternStyle style, i64 offset_seconds)
 {
     auto formats = get_time_zone_format(locale);
     if (!formats.has_value())
-        return OptionalNone {};
+        return {};
 
     auto number_system = get_preferred_keyword_value_for_locale(locale, "nu"sv);
     if (!number_system.has_value())
-        return OptionalNone {};
+        return {};
 
     if (offset_seconds == 0)
-        return String::from_utf8(formats->gmt_zero_format);
+        return MUST(String::from_utf8(formats->gmt_zero_format));
 
     auto sign = offset_seconds > 0 ? formats->symbol_ahead_sign : formats->symbol_behind_sign;
     auto separator = offset_seconds > 0 ? formats->symbol_ahead_separator : formats->symbol_behind_separator;
@@ -271,23 +265,23 @@ static ErrorOr<Optional<String>> format_time_zone_offset(StringView locale, Cale
     offset_seconds %= 60;
 
     StringBuilder builder;
-    TRY(builder.try_append(sign));
+    builder.append(sign);
 
     switch (style) {
     // The long format always uses 2-digit hours field and minutes field, with optional 2-digit seconds field.
     case CalendarPatternStyle::LongOffset:
-        TRY(builder.try_appendff("{:02}{}{:02}", offset_hours, separator, offset_minutes));
+        builder.appendff("{:02}{}{:02}", offset_hours, separator, offset_minutes);
         if (offset_seconds > 0)
-            TRY(builder.try_appendff("{}{:02}", separator, offset_seconds));
+            builder.appendff("{}{:02}", separator, offset_seconds);
         break;
 
     // The short format is intended for the shortest representation and uses hour fields without leading zero, with optional 2-digit minutes and seconds fields.
     case CalendarPatternStyle::ShortOffset:
-        TRY(builder.try_appendff("{}", offset_hours));
+        builder.appendff("{}", offset_hours);
         if (offset_minutes > 0) {
-            TRY(builder.try_appendff("{}{:02}", separator, offset_minutes));
+            builder.appendff("{}{:02}", separator, offset_minutes);
             if (offset_seconds > 0)
-                TRY(builder.try_appendff("{}{:02}", separator, offset_seconds));
+                builder.appendff("{}{:02}", separator, offset_seconds);
         }
         break;
 
@@ -296,16 +290,16 @@ static ErrorOr<Optional<String>> format_time_zone_offset(StringView locale, Cale
     }
 
     // The digits used for hours, minutes and seconds fields in this format are the locale's default decimal digits.
-    auto result = replace_digits_for_number_system(*number_system, TRY(builder.to_string()));
-    return TRY(String::from_utf8(formats->gmt_format)).replace("{0}"sv, result, ReplaceMode::FirstOnly);
+    auto result = replace_digits_for_number_system(*number_system, builder.string_view());
+    return MUST(MUST(String::from_utf8(formats->gmt_format)).replace("{0}"sv, result, ReplaceMode::FirstOnly));
 }
 
 // https://unicode.org/reports/tr35/tr35-dates.html#Time_Zone_Format_Terminology
-ErrorOr<String> format_time_zone(StringView locale, StringView time_zone, CalendarPatternStyle style, AK::UnixDateTime time)
+String format_time_zone(StringView locale, StringView time_zone, CalendarPatternStyle style, AK::UnixDateTime time)
 {
     auto offset = TimeZone::get_time_zone_offset(time_zone, time);
     if (!offset.has_value())
-        return String::from_utf8(time_zone);
+        return MUST(String::from_utf8(time_zone));
 
     switch (style) {
     case CalendarPatternStyle::Short:
@@ -313,14 +307,14 @@ ErrorOr<String> format_time_zone(StringView locale, StringView time_zone, Calend
     case CalendarPatternStyle::ShortGeneric:
     case CalendarPatternStyle::LongGeneric:
         if (auto name = get_time_zone_name(locale, time_zone, style, offset->in_dst); name.has_value())
-            return String::from_utf8(*name);
+            return MUST(String::from_utf8(*name));
         break;
 
     case CalendarPatternStyle::ShortOffset:
     case CalendarPatternStyle::LongOffset:
-        if (auto formatted_offset = TRY(format_time_zone_offset(locale, style, offset->seconds)); formatted_offset.has_value())
+        if (auto formatted_offset = format_time_zone_offset(locale, style, offset->seconds); formatted_offset.has_value())
             return formatted_offset.release_value();
-        return String::from_utf8(time_zone);
+        return MUST(String::from_utf8(time_zone));
 
     default:
         VERIFY_NOT_REACHED();
diff --git a/Userland/Libraries/LibLocale/DateTimeFormat.h b/Userland/Libraries/LibLocale/DateTimeFormat.h
index 7fe86a84321..91b84b18154 100644
--- a/Userland/Libraries/LibLocale/DateTimeFormat.h
+++ b/Userland/Libraries/LibLocale/DateTimeFormat.h
@@ -6,7 +6,6 @@
 
 #pragma once
 
-#include <AK/Error.h>
 #include <AK/Optional.h>
 #include <AK/String.h>
 #include <AK/StringView.h>
@@ -189,44 +188,44 @@ CalendarPatternStyle calendar_pattern_style_from_string(StringView style);
 StringView calendar_pattern_style_to_string(CalendarPatternStyle style);
 
 Optional<HourCycleRegion> hour_cycle_region_from_string(StringView hour_cycle_region);
-ErrorOr<Vector<HourCycle>> get_regional_hour_cycles(StringView region);
-ErrorOr<Vector<HourCycle>> get_locale_hour_cycles(StringView locale);
-ErrorOr<Optional<HourCycle>> get_default_regional_hour_cycle(StringView locale);
+Vector<HourCycle> get_regional_hour_cycles(StringView region);
+Vector<HourCycle> get_locale_hour_cycles(StringView locale);
+Optional<HourCycle> get_default_regional_hour_cycle(StringView locale);
 
 Optional<MinimumDaysRegion> minimum_days_region_from_string(StringView minimum_days_region);
 Optional<u8> get_regional_minimum_days(StringView region);
-ErrorOr<Optional<u8>> get_locale_minimum_days(StringView locale);
+Optional<u8> get_locale_minimum_days(StringView locale);
 
 Optional<FirstDayRegion> first_day_region_from_string(StringView first_day_region);
 Optional<Weekday> get_regional_first_day(StringView region);
-ErrorOr<Optional<Weekday>> get_locale_first_day(StringView locale);
+Optional<Weekday> get_locale_first_day(StringView locale);
 
 Optional<WeekendStartRegion> weekend_start_region_from_string(StringView weekend_start_region);
 Optional<Weekday> get_regional_weekend_start(StringView region);
-ErrorOr<Optional<Weekday>> get_locale_weekend_start(StringView locale);
+Optional<Weekday> get_locale_weekend_start(StringView locale);
 
 Optional<WeekendEndRegion> weekend_end_region_from_string(StringView weekend_end_region);
 Optional<Weekday> get_regional_weekend_end(StringView region);
-ErrorOr<Optional<Weekday>> get_locale_weekend_end(StringView locale);
+Optional<Weekday> get_locale_weekend_end(StringView locale);
 
-ErrorOr<String> combine_skeletons(StringView first, StringView second);
+String combine_skeletons(StringView first, StringView second);
 
-ErrorOr<Optional<CalendarFormat>> get_calendar_date_format(StringView locale, StringView calendar);
-ErrorOr<Optional<CalendarFormat>> get_calendar_time_format(StringView locale, StringView calendar);
-ErrorOr<Optional<CalendarFormat>> get_calendar_date_time_format(StringView locale, StringView calendar);
-ErrorOr<Optional<CalendarFormat>> get_calendar_format(StringView locale, StringView calendar, CalendarFormatType type);
-ErrorOr<Vector<CalendarPattern>> get_calendar_available_formats(StringView locale, StringView calendar);
-ErrorOr<Optional<CalendarRangePattern>> get_calendar_default_range_format(StringView locale, StringView calendar);
-ErrorOr<Vector<CalendarRangePattern>> get_calendar_range_formats(StringView locale, StringView calendar, StringView skeleton);
-ErrorOr<Vector<CalendarRangePattern>> get_calendar_range12_formats(StringView locale, StringView calendar, StringView skeleton);
+Optional<CalendarFormat> get_calendar_date_format(StringView locale, StringView calendar);
+Optional<CalendarFormat> get_calendar_time_format(StringView locale, StringView calendar);
+Optional<CalendarFormat> get_calendar_date_time_format(StringView locale, StringView calendar);
+Optional<CalendarFormat> get_calendar_format(StringView locale, StringView calendar, CalendarFormatType type);
+Vector<CalendarPattern> get_calendar_available_formats(StringView locale, StringView calendar);
+Optional<CalendarRangePattern> get_calendar_default_range_format(StringView locale, StringView calendar);
+Vector<CalendarRangePattern> get_calendar_range_formats(StringView locale, StringView calendar, StringView skeleton);
+Vector<CalendarRangePattern> get_calendar_range12_formats(StringView locale, StringView calendar, StringView skeleton);
 
-ErrorOr<Optional<StringView>> get_calendar_era_symbol(StringView locale, StringView calendar, CalendarPatternStyle style, Era value);
-ErrorOr<Optional<StringView>> get_calendar_month_symbol(StringView locale, StringView calendar, CalendarPatternStyle style, Month value);
-ErrorOr<Optional<StringView>> get_calendar_weekday_symbol(StringView locale, StringView calendar, CalendarPatternStyle style, Weekday value);
-ErrorOr<Optional<StringView>> get_calendar_day_period_symbol(StringView locale, StringView calendar, CalendarPatternStyle style, DayPeriod value);
-ErrorOr<Optional<StringView>> get_calendar_day_period_symbol_for_hour(StringView locale, StringView calendar, CalendarPatternStyle style, u8 hour);
+Optional<StringView> get_calendar_era_symbol(StringView locale, StringView calendar, CalendarPatternStyle style, Era value);
+Optional<StringView> get_calendar_month_symbol(StringView locale, StringView calendar, CalendarPatternStyle style, Month value);
+Optional<StringView> get_calendar_weekday_symbol(StringView locale, StringView calendar, CalendarPatternStyle style, Weekday value);
+Optional<StringView> get_calendar_day_period_symbol(StringView locale, StringView calendar, CalendarPatternStyle style, DayPeriod value);
+Optional<StringView> get_calendar_day_period_symbol_for_hour(StringView locale, StringView calendar, CalendarPatternStyle style, u8 hour);
 
-ErrorOr<String> format_time_zone(StringView locale, StringView time_zone, CalendarPatternStyle style, AK::UnixDateTime time);
+String format_time_zone(StringView locale, StringView time_zone, CalendarPatternStyle style, AK::UnixDateTime time);
 Optional<StringView> get_time_zone_name(StringView locale, StringView time_zone, CalendarPatternStyle style, TimeZone::InDST in_dst);
 Optional<TimeZoneFormat> get_time_zone_format(StringView locale);