The direction of dependency is from your program to the console specific stuff. You can write a platform library which is linked to your program without releasing that library.
> modern boomer shooters
I didn't say for boomer shooters. It's a general 3D game engine.
> just use Unity, Unreal or occasionally Godot instead of the actual Quake engine.
Because they are popular and familiar, not because they did a serious evaluation.
Also my comment was about Irrlicht/Ogre, etc.