"Rust is faster and safer! Port it! If you don't do it, I'll do it myself, because AI can do everything a programmer can, including the stuff you don't want to do. Ship it!"
that will ensure the new codebase can still be well understood and can continue to grow in foreseeable future
or you can just vibe the whole experience if it is a legacy project with all the specs and edge cases known.
since bun rewrite is neither of the case, it will be a crapfest soon enough.