Fair enough, I don’t think I have an direct answer to the big picture of your question but in my own experience improving my confidence and the mentality I’ve adopted to do so has in turn reshaped how I view myself. So as you stated there might be an overlap of the two topics.

I’m not trying to advertise it (I have it as a pdf and would offer to send you a copy if I knew how to do that on here) but the book i was referring to is called “The confident mind” It’s by Nate Zinsser. It felt a little dry but it isn’t trying to be a science fiction novel and makes it points very well. An example being from my last comment just repeating something to yourself over and over leads to you starting to believe it. It also uses pro athletes and their mentality and talk about how one could apply the same approach to everyday life. It’s not earth shattering revelations, but for me it did connect things in a way that helped shift my perspective.