The typescript language server does a great job supporting rename refactors for string unions. It doesn't get much easier than that and is no harder than string enums, in my view.
(I've done crazy things like use emoji named types in string unions and then used F2 to rename refactor them to a different emoji or name and not needed to worry if it missed any emoji literals.)
The only thing missing from both string enums and string unions is something to support [Symbol.iterator]() to iterate through the available options, but at this point I find that easier to write DRY with string union types (especially with typeof/keyof meta-magic) rather than string enums.
