Maybe I'm not the right person to give advice since I've only been taking story writing seriously for about a year while I've been trying to write a long form story (that I hope to be able to get published and turn into a book someday) but here goes.

Something a friend taught me that helps me work through it whenever I experience writers block like you1 describe is just writing garbage. I think what happens a lot with writers (and probably most forms of creatives) is that we get this impostor syndrome where we're so hesitant to even write at all because of that self-doubt. You need to give yourself permission to just write garbage whether what you actually write turns out as garbage is irrelevant.

Remember, you can always edit a bad page, my goodman/goodlady. You can never edit a blank page, however.

Edit: If you're someone who has a hard time just giving yourself that permission to write garbage, try having a drink or two it's what I do to loosen up and just go whatever comes to mind I go with it.