It is unrealistic to expect one server to have everything for every language. What does Haskell do with "extract to method"? What does C++ do with "convert to point-free"? This isn't like HTML where browsers were deliberately fragmented for strategic reasons, languages have these differences for their own good reasons.

But sharing as much as possible and harmonizing as much as possible is a huge step forward, even if each language still has a bit around the edges to implement. At least they agree on language, fundamental communication model, common functionality, etc.

So when using rust-analyzer with Emacs, I've noticed that it lists code transformation suggestions based on where your cursor is, and you can optionally choose to apply those.

That seems to be generic, e.g., rust-analyzer provides the suggestions, and lsp-mode is just listing them. Though I don't know that for sure.