Joyce seems to me to go a long way to prove himself. Bloom is not a well-educated man, but he believes in learning and culture and is amusingly didactic on every issue. His wife Molly regards him as a failure because of his job history, but they have a stable home, have raised a daughter who is doing well, and live in comfort, while another character, Simon Dedalus, also portrayed as a friendly and kind man, sees his belongings auctioned off and cannot support his children. When Simon's son Stephen is in trouble at the end of the book, Bloom rescues him from the police, takes him home, and serves him cocoa, all the time identifying Stephen with his own dead son, Rudy. Whenever Joyce is comparing Bloom with other people, Bloom seems to come off as a better man.
Bloom is also a flawed and somewhat perverse human being.
He has himself been unfaithful to Molly, mainly with prostitutes, likes pornography, and in Molly's sololiquy, sexual behavior of his is described or hinted at which she herself regards as not normal. Since Bloom in toto is a familiar, friendly and good human being, it is likely that he is also perverse by virtue of being human and not by virtue of being Jewish. An essay on Joyce I consulted suggested that the model for Bloom was a man who once rescued Joyce from a confrontation, much as Bloom rescues Stephen. I know nothing else about Joyce's Jewish friends, or his exposure to Jewish culture, but Ulysses contains its own explanation for Joyce's interest. There is a pronounced trend in our century to look for truth on the margins.