Comment by boje

>Godot locks you into the Godot way of doing things. MonoGame is a thin cross-platform abstraction over platform APIs for sprite rendering, audio playback, input, and font, leaving you to build your game engine yourself however you like.

That might be changing: https://github.com/godotengine/godot/pull/110863

Besides, there's a lot of value Unity, Unreal and Godot provide besides just the GUI in ways similar to and different from MonoGame.