I’d say it’s realistically probably both. The only reason I know for sure about how I look is because I regularly hear it from others, not just strangers but also partners. But I’m still prone to moments/days of quaking self-doubt, and during those times I have to rely on previously built self -assurance and a strong resolution to not compare myself to others and focus on myself and my journey. If anyone were to ever criticize my looks or clothes during those moments (even just a little) I would definitely crumble. Another thing that I think plays a big role in self-regard is personality traits, including disorders. I consider myself knee deep in the narcissism spectrum, so I automatically have reserves of self esteem that comes from disdaining others and worshipping myself. Of course this means I’m also very vulnerable to injuries to my ego.

It’s a mixed bag, but I really don’t think anyone could have confidence and self esteem without validation from others