Imposter syndrome is a hell of a thing. Doing something near daily for more than a decade cannot defeat the doubt that comes in from a temporary loss of passion, shaky knowledge of the new, and such a crippling fear of making a mistake I choose to procrastinate and make everything ultimately worse.
Doing the scary things and seeing a positive result is the best remedy, but seeing that in the moment is nearly impossible. I recently learned about Brag Documents. You note down all the great stuff you do as you do it so as not to forget. While it's intended to help with performance reviews I think I can see it helping when reviewed in times of doubt, and fostering a 'I know I can do this' attitude.
Now I just need to gain the confidence to feel ok with bragging.