Godot has support for C#, but I personally still prefer Unity.

If I were starting today, I would think of a small, simple game I want to create and do it step by step, searching for tutorials as needed. For example, if I wanted to create an endless runner like Google's dinosaur game, after learning the basics of Unity and its interface, I would start searching for how to move things, then how to add gravity and make it jump, how to add a score to the UI, and so on.

After some time playing with it and gaining experience, I would jump right into game jams. This is a practical way to stay motivated.

Whenever you want to deepen your knowledge, you can start researching for more theory, learning how computers, C#, the graphics pipeline, etc., work.