I'd suggest godot instead of unity. Godot is open source and quite powerful, unity is proprietary and might decide someday to charge you every time someone downloads your game. (Unity floated this already, leading to a huge backlash so they walked it back, but that suggests to me that they want to do it and are testing the waters but ultimately decided to put that particular money grab on hold, for the moment. Godot will never do something like that, because it's open source.)