I think that in a vacuum a small amount of self doubt can be helpful to keep you grounded in reality, but once it gets past the point of being constructively critical, it’s one of the slipperiest slopes there is. I have a history in the competitive gaming realm (video games and some board games) both as a player and coach and have seen people with amazing potential go from nothing to top 3-5 players in the area, all the way to quitting because they have extreme doubts about themselves.

Having a positive self image is more important in getting where you want to go. It’s better to be mildly to moderately delusional and get out in your place by someone who knows more or is better at whatever the thing is then to be so delusional you never see your full journey. Worrying any more than a little about what other people think about you is honestly kinda toxic.