Maybe I am wrong, but I think Unreal engine will let you do anything and you can actually compete with the big studios, performance and feature wise. The only

Maybe I am wrong, but I think Unreal engine will let you do anything and you can actually compete with the big studios, performance and feature wise. The only reason someone can't actually compete, is man-hours available. Some things are just very time-consuming to implement. But this last point applies to any engine, even the ones the big studios use. About open source, just check Godot. And Godot is a competitor to Unity, in the 'learn this engine and you will have to keep using it' market. Which I think is fine for Indies.