I mean, immense corporate codebases is the bread and butter of IntelliJ Idea and where it has a reputation to shine. I don't doubt that you are commenting in good faith, but the exact opposite of your experience is what most people have been saying about it over the years. Have you considered reporting the issue to them?

My experience of vscode LSPs across several languages is that they too use many GBs of RAM over time, just what you would expect from an IDE (and not from a text editor), while delivering pretty poorly feature-wise (unlike idea-based editors, I can't trust vscode to know how to rename variables across languages e.g. from models into templates/SQL, and that's a pretty essential bar to cross in my book).