> I usually propose that we unify the common subsets of the Cyrillic, Greek, Latin, and Mathematical glyphs which usually finally drives home the point.

That would be an awesome compact encoding scheme (and also help with the next 4million emojis)! And given the relatively higher importance of those CyrGrLat, it would force wider proper support that would resolve the issues you raised, which are all app-dependent

> But, they are invisible to the end user

Apps make them visible, some even do that for whitespace chars to highlight the difference

> can disappear while copying and pasting

broken clipboards can be fixed? They somehow manage to retain rich text formatting, surely they cna retain language markers?

> you have to rely on the original author even putting them there in the first place!

Nope, the author's input app can handle that just like the original author doesn't need invisible joiners to use composed emojis