I always used julia with the ess layer in spacemacs, are there any conflict if you install both? I also use R and need ESS.
I also added some more key bindings: https://github.com/syl20bnr/spacemacs/pull/9920
I made a (failed) attempt to fix the language server: https://github.com/gdkrmr/lsp-julia
Did you get the language server to work?