I feel that the best cure to these various forms of procrastination(paralysis by analysis, choice overload, writer's block) is simply to leave your feelings and emotions aside for now and power through it even though it doesn't feel like it. All other treatments which I see mostly as mind games(e.g. psyching yourself up, trying to rationalise or explain away your feelings) have very little effect if any.
It's the best cure when it works. But what to do when it doesn't?
This is the one place where the Dunning-Kruger effect is actually beneficial. Have Confidence (maybe false) in your ability and jump in to get started. Learn as you do and iterate amongst the various choices i.e. "trial and error" approach.
If I summarize it in one sentence: keep moving, and get better.