I really hope that this means that we can some day get a Jetbrains Java LSP. I would pay for an Intellij Ultimate subscription just to get access to such a thing.
so being strictly emacs, will really limit your choices, and honestly waste your time
It is really easy to navigate only from the keyboard. It uses vim-style keybindings for everything, so you don't have to do all the weird hand contortions that happen a more traditional emacs-style interface. When you do access functions, they are handled with multi-keystroke gestures while you're in command mode. The keystrokes are effectively navigating through a menu tree. There's a minibuffer at the bottom of the screen to help you navigate, so you don't have to rote memorize everything, but anything you do use often enough to memorize can be accessed in 2-4 keystrokes.
Some of the plugins are just amazing. Projectile - a project management and navigation sidebar - has really good ergonomics compared to what I'm used to with graphical IDEs. Magit is a fantastic and powerful git interface, and the only in-editor git interface I'll actually use; in any other IDE I'll just use git from the command line.
I've got to mention orgmode, of course. I'm not sure I can articulate why I like it so much; it's kind of like a vi-style editor interface where it's hard to grok without putting in some time, but those who do put in the time tend to fall in love.
I will agree that emacs's language support is spotty compared to vscode, but in this day and age that's true of any editor that isn't vscode. And it also lacks that really deep melding with the language that you get with IDEs that are all-in on one platform like IntelliJ IDEA and Visual Studio. But in general it's kind of an outlier in terms of popularity-to-polish ratio.