I am not sure which issues you are talking about in context of Android-DateUtils and PrettyTime-library. But I know for sure that Android-DateUtils does not perfectly manage the plural rules of various languages (especially not slavish languages or arabic because it only knows singular and one plural form which is too simple). See for example this Android-issue. About the PrettyTime-library, the same objection is valid if you consider Arabic - see the source.
My recommendation:
Try out my library Time4A (a new AAR-library). Then you can use this code to process a millisecond-input and to produce a localized minute-string:
// input
long millis = 1770123;
// create a duration
Duration<ClockUnit> duration = Duration.of(millis, ClockUnit.MILLIS);
// normalization to (rounded) minutes
duration = duration.with(ClockUnit.MINUTES.rounded());
String s = PrettyTime.of(Locale.ENGLISH).print(duration, TextWidth.WIDE);
System.out.println(s); // 30 minutes
Example for Korean (answer to comment of @Gabe Sechan):
String s = PrettyTime.of(new Locale("ko")).print(duration, TextWidth.WIDE);
System.out.println(s); // 30분 (korean translation of "30 minutes")
Example for Arabic (right to left):
String s = PrettyTime.of(new Locale("ar")).print(duration, TextWidth.WIDE);
System.out.println(s); // ٣٠ دقيقة
This solution currently supports ~90 languages (more than in PrettyTime-library) and three text widths (full, abbreviated or narrow). Accurate pluralization handling is automatically included. Time4A uses its own language resources based on CLDR-data (independent from Android). But you are free to override those resources by defining your own assets (in UTF-8).
About normalization: I just showed the variant which you have described in your question. However, there are many more ways how to normalize durations in Time4A(J). This page will give you more ideas how to use that feature.
If you still miss some languages then just tell me, and I will support it in the next versions of Time4A. Currently supported languages can be found in the tutorial.