There's a mental disorder called body dysphoria that's similar to gender dysphoria. Instead of feeling that you're the wrong sex to match your gender, you feel there's something wrong with your body when their really isn't. Most people with it perceive themselves as having some flaw or disfigurement they don't actually have. With Russ, it's like he has the inverse of that. He doesn't perceive defects he actually has, which is why he thinks he's a 9 or 10 (and ranking your appearance by number is childish in the extreme, but that's another topic). I don't think he's trying to puff up his ego, I think he really believes he's very handsome, along with the idea that his big break hasn't happened because other people are keeping him down, not because he no talent in his chosen field.