I've been using vim for over 20 years as my primary editor. I'm faster and more comfortable in it than I am in any other editor, but I still feel like a vim noob
I still have to look up how to do things I rarely do (like insert the contents of another file at the cursor position). And I don't really use many (if any) of vim's intermediate features, let alone advanced ones.
I've tried various ways to get more fluent, but nothing really stuck or kept my interest. This has always annoyed me a bit...
I've been using vim for 20 years as well, for everything other than Java code. I type my .vimrc by hand on each new machine to set a half dozen options.
Of the intermediate features, I use tabs and, more recently, split windows.
My favorite 'advanced' feature is visual block selection and replacement over multiple lines - super convenient.