That's an interesting thing you've got there. If this were standardized I might actually take the time to learn some of them. My own language has a whole pile of diacritical marks that I never use, I just transliterate everything to ASCII and call it a day. This obviously is very broken but what with every editor and every OS having their own way of doing super/subscript and various composition method it never seemed worth the trouble. But some people can get very offended when you don't write their name properly. German has picked some sensible transliteration defaults now that allow you to write German without resorting to special letters. But in other languages they would be horrified by such a thing. And for things like superscripts, subscripts and so on it is even worse.

I didn't realize Dutch had a lot of diacritics! I often use Emacs's builtin input methods in Emacs, for example when writing in Spanish, but Compose works in Emacs too. Because I don't yet have any Wayland devices, Android is the only operating environment where I can't use that .Xcompose file.