It seems you got something wrong, take a look at: GitHub - KronicDeth/intellij-elixir: Elixir plugin for JetBrain's IntelliJ Platform (including Rubymine) · GitHub. This plugin is way before elixir-ls was a thing and it has amazing support, and a better set of features compared to all other plugins on the market.
I was using it back in the day, however as you said, once you learn how elixir works, you don’t need these tools that much anymore.
