https://emacs-lsp.github.io/lsp-mode/page/remote/ suggests that LSP under TRAMP is basically there, though I haven't had occasion to try it.
cd /sshx:host: ls any remote command
https://emacs-lsp.github.io/lsp-mode/page/remote/ suggests that LSP under TRAMP is basically there, though I haven't had occasion to try it.