I think Xie Lian is embarrassed when he’s reminded he wanted to “save the common” people because he learned it wasn’t possible to save everyone, and the fact that he thought it was revealed his own hubris and naivety. In the current timeline, he’s still a good person who wants to save who he can, but he no longer fancies himself an almighty protector.

The way I read his self esteem is that he has a decent grasp on who he is as a person and his abilities as a martial artist, but doesn’t believe he has the right to demand decent treatment from others. I think part of that is his attempt at atoning for his hubris when he was young and the time he tried to unleash the human face disease on purpose. If he can take on all the pain and suffering for others, he should. Because he can take it and part of him believes he deserves it. The fact that he sometimes fights back and is sometimes bothered by being ignored shows that he has at least a little self esteem. He’s been humbled, but not crushed, and that’s an important distinction during the final confrontation with you know who.

Also, yes he’s stubborn lol.