When you say RCS is a mess on Android, what do you mean? I personally have not had issues.

What would be useful is if Lemmy had some way to allow communities to set if downvotes are allowed or not

Agreed here. On Reddit, some communities use downvotes very effectively as “this information is incorrect” so that mods don’t have to remove disinformation all the time. Others it turns into a popularity contest, which isn’t great.