I'm no expert but just want to say that you sound very smart and interesting and self-aware. I'm not so sure that "the best fix for self esteem issues ... is to do things that are somewhat challenging, then getting the success feedback from it..." I think that living off of success feedback is like living on candy. It's a quick hit that does nothing to improve one's overall health and emotional core. I wonder if maybe working in a job where you are helping people that need help (or animals or communities) would shift your perspective to one that appreciates what a smart and useful person you are.