Sources: https://stackoverflow.com/a/78071275 & https://nrogap.medium.com/install-ruby-lsp-in-vs-code-128f02571ea0
Outside your main project, create a folder :
Make sure to install a ruby version >= 3.0.0
with YJIT (I'm using rbenv):
$ RUBY_CONFIGURE_OPTS="--enable-yjit" rbenv install 3.2.2