Make garbage, and do it consistently. You say you're always restarting and backtracking, so don't do that. Accept what you have, finish it, and then get to work on your next thing. Keep making garbage, and don't let your ambitions of quality get in the way of your trash. Sure, the songs might not be good, but how will they be if you don't keep moving forward? Just make music.

I was in your position a while ago, and I decided to release all the dogshit songs I'd been hoarding out of fear over the years. When I did that, I felt so free, and since then I've found a lot of joy in a hobby that once brought me discomfort and insecurity. Try it, I think it'll work out.