I think Godot is a possible contender as well. There are a few non-game applications made with it, and they've recently added a docs page tailored to non-game a

I think Godot is a possible contender as well. There are a few non-game applications made with it, and they've recently added a docs page tailored to non-game application development: https://docs.godotengine.org/en/stable/tutorials/ui/creating_applications.html https://docs.godotengine.org/en/stable/tutorials/ui/creating...