I agree - working on nimlsp would benefit a lot of different editors, so is the best place to invest the work.
My VSCode instance uses nimlsp (VSCode + [vscode-nim-lsp plugin](https://marketplace.visualstudio.com/items?itemName=bung87.vscode-nim-lsp) \+ nimlsp). I would be very happy to help the effort in any way I can, including testing.