I would be careful not to let him find that a habit of self-pity excuses him from reasonable discipline. Encourage his self-esteem, but don't change expectations. Rather, frame the expectations as flowing from a positive and patient view of his potential.
The tack I take with my kids is this: I correct you because I see that you have what it takes to get this. I'm not trying to teach ballet to a bear. You will get to be good at this. You don't have to be perfect. You are great for eleven. You don't have to get it in a day. I correct you, though, because we're working on the fine man you'll be when you're 18 and 21 and beyond. That man is going to need discipline when he's young, and gradually self-discipline as he grows. I see that man now, but you aren't going to become the best version of yourself by accident. No one does. I needed correction when I was your age. Your teacher did, Father did, everyone does. The few who don't seem to have their own things to learn, who seem to do it all right, they need to learn things like how to try things where they might make a mistake. Even we older people still need correction now; that is why we examine our consciences and go to confession.
The other thing I have learned is from a marriage expert: Give at least 5 positive comments for each negative comment, and give the negative comments as complaints about behavior, not attacks on the person, let alone contempt. If a person lacks ability, that is not their fault. If they lack motivation, you'll never criticize that into them, at least never in a way you'd want to do it.
As for the bed-wetting, that is an issue that needs to be dealt with, but I would frame it as a problem you'll help him with, that you will figure out how to deal with together. It happens, it is no sin, it is nothing to be ashamed of. With everything, you're there on his side: Not a critic, but a coach, and one who will not rest until he realizes his full potential!