XeTeX handles Unicode fine, but that's definitely one area where TeX shows its age and its extensibility didn't, I think, allow Lamport to make a real difference.
I have heard about it, but it isn't viable for me to switch to it because most academic journals and conferences have templates incompatible with XeTeX, or directly ask for the sources and compile them with pdflatex.
This is the same reason why it isn't viable for me to switch to typst either, by the way. I hope it gains popularity and ends up as a standard displacing (or along with) pdflatex.
I'm not a vim user but my understanding is that it has native Unicode support. Software with old-school UI but adapted to current needs (or where needs just didn't change) is fine, but it's not the case of LaTeX.