"Lightweight" and "small" isn't the same as simple. People seriously gotta stop recommending godot to beginners. It's good as a general engine, but a lot to take in for a beginner.
Pygame is a great choice. I would add Love2D as a similar alternative if you don't jive with Python.
Off topic but Godot has a serious cult problem. Say anything that could possibly be interpreted as negative about it, and you're going to get someone writing a very emotional response. It's pretty much at the Apple fan boy level, which is bad but mostly weird.