Which one have you spent the most time with?
The engine I tried was too hard!
Totally new and don't know what to pick?
If you are still learning how to program, you might be able to pick up Unity or Unreal or Godot no-problem, some people do.
However, in my experience most people need to focus on just one or two things at a time. I recommend Pico8 (or picotron if looking at Pico8 hurts your eyes) becuase there just isn't as much to learn before you can start practicing the idea-to-math thing. Pico8 also doesn't do much for you, so you'll have to take its few tools and get creative.
I've seen enough people get stuck in the "I follow tutorials but I don't feel like I'm learning anything" trap to strongly urge you away from the more popular engines. Learn to bicycle first, then you can try a motorcycle.