I think I have hit the point where I don't find any value in learning anything that isn't F/LOSS. Not because I'm a F/LOSS zealot (though that's part of it) but because I see things that are commercial / proprietary as evolutionary dead-ends.
Case in point: I have a license for App Game Kit that I got through Humble Bundle. I'm sure it's a nice program but I have no interest in making anything with it when there's engines like Godot, TIC-80, and PyGame to scratch my game-making itches.