Absolutely agree. I love Elixir but the editor integration has always been unfortunately second-class. The happy paths in VSCode work well enough with the ElixirLS, but there are a few flaws that are a quite a bummer. One major one is no rename / refactor functionality (seriously?!) and a more Phoenix-specific issue is trying to contend with auto-complete in templates, which is no fun.
I like VSCode fine, but I'd definitely be interested in a Jetbrains level IDE for Elixir stuff.
It frustrates me to no end that we have three separate, incomplete LSP implementations for Elixir, none of them collaborate and none of them are first party tools from the language maintainers - they're all minor community figures. They are one of the jankiest part of my experiences working with the language and it's very disappointing to live with when I also use rust-analyzer all the time and have seen the polished & productive version of LSP support.
FWIW I have moved to next-ls because IIRC José is a premium sponsor of the project, so I feel safe relying on it for the time being. Agree that the duplication is unnecessary and wasteful.
I like VSCode fine, but I'd definitely be interested in a Jetbrains level IDE for Elixir stuff.