> game design is a rabbit hole

Game engine design is a rabbit hole :)

Game design is the ultimate lockbox - you're unlocking an entire imaginary world which has some platonic existance in your mind.

And since you mentioned Luanti, it deserves to be much better known as a credible open alternative to Minecraft. You could do a lot worse then designing/prototyping your game with Luanti as the game engine.

https://www.luanti.org/