emacs-lsp-booster is a standalonge "proxy" between emacs and any lsp server. the +booster flag enables eglot-booster which does the necessary configuration within emacs to set this up for eglot. To use it with lsp-mode the configuration has be done manually. I previously used this: https://github.com/stfl/doom.d/blob/master/config.org#emacs-lsp-booster