Back in the early Unreal Engine 4.x days, Epic created a really neat plugin called PythonScriptPlugin, which allows you to use the UObject Reflection system to script the Editor via Python. On startup, it generates a nice unreal.py stubs file for your LSP.
Neat, right?
Only problem is that it wasn't designed to handle the staggering number of reflected classes & structs, and today, the generated stubs file for a blank Unreal 5.7 project is half a million (501,714, to be exact) lines long.

