What you could do is search up the Gamemaker tutorials and use Godot with those tutorials if they're not too different.
As for art? I also suck at art. It took a hell of a lot of practice for me to get dragons down, and I still can't do a front view. All I can really say here is practice A LOT.
Music? Beepbox. It's really good for music, and your music is yours, no copyright and no credits needed. I never worked with a beepbox mod before, but Spoonsamurai uses Ultrabox and everyone else here uses base Beepbox and look what they're cooking. My tip, beepbox-wise, is set the drop down that says "easy :)" on it to say "expert" bc that opens up all the spaces.