This is something that only humans care about, not computers. And humans can be accommodated by prettyprinting - or, in a pinch, by roundtrip conversion from an ASCII-only format to a "rich", Unicode-based one, and back. But let computers have their simple, ASCII-based identifier names. E.g. https://en.wikipedia.org/wiki/Punycode is a thing, and is routinely used for "native-language" domain names. But guess what, these domain names are still ASCII under the hood!
(Indeed, we should arguably move away from the notion of a single character string as the only human-facing semantics that an identifier is associated with-- there should be a higher layer, perhaps with multiple choices of e.g. native language, formatting and the like. Human facing semantics are closer to "literate" documentation than to anything that compilers should have to deal with. Yes, the "native", underlying representation should still be something that we can somehow make sense of - I'm not saying that our identifiers should be GUIDs or anything like that! But it will only be resorted to in a pinch.)
(Indeed, we should arguably move away from the notion of a single character string as the only human-facing semantics that an identifier is associated with-- there should be a higher layer, perhaps with multiple choices of e.g. native language, formatting and the like. Human facing semantics are closer to "literate" documentation than to anything that compilers should have to deal with. Yes, the "native", underlying representation should still be something that we can somehow make sense of - I'm not saying that our identifiers should be GUIDs or anything like that! But it will only be resorted to in a pinch.)