The terminal-based editors like vim/emacs exist. Ideally they should work just as well the GUI-based editors, no matter what text files they're tasked to open and edit.

As for the scripts, Unicode is slowly rounding up with the actually used scripts, but it's still not quite there yet.

And then there are emojis, of course, which we get new sets every couple of years, which makes the life of the terminal emulators simply terrible. There is simply no good way to support emoji sequences in the terminal, I believe. Consider e.g. HEART ON FIRE (READ HEART, ZWJ, FIRE) and PHOENIX (BIRD, ZWJ, FIRE) emojis: the terminal emulator may or may not be aware of the existences of those emoji sequences depending on which version of ICU it is build against, and even if it is aware of them, then the currently selected font may not have the required glyphs so it has to fall back to the fallback display (4 cells of two basic emojis vs. 2 cells of the combined glyph). And of course, the font itself may have completely bonkers dimensions for its glyphs: as I understand it, Google's Noto Emoji font has glyphs for playing cards that are 1.5 cells wide even though they're supposed to be narrow (only 1 cells wide); there is nothing much the terminal emulator can do with that.