To me, the way his character became more insulated in later seasons was also partially due to a sense of shame: of course, he felt wronged but he also felt obviously responsible for what happened to Connor and the rest of his makeshift family.

Probably my reading of Wesley is too harsh, but to me he just came across as more wrapped-up in himself and his friends not hearing his side of the side in that whole saga, rather than being horrified at the events he had set into motion that led to his friends baby ending up in a Hell dimension. Like that's actually really dark and horrific stuff that you could spend the rest of your life beating yourself up for, but instead "I had my throat cut and all my friends abandoned me" seemed to be the biggest thing that he took away from it all IMO. Even when he did reach out and say rescue Angel in Deep Down, I always felt like dramatically taking Angel back to the hotel and then disappearing was partly about him being self-righteous and proving a point to his former friends that see I'm not the jerk that you ungrateful people are all painting me as

I'm not saying that Wesley didn't regret what happened to Connor, but to me it always seemed like he was really focused on how his friends were the ones who had betrayed him by not understanding that he had good intentions really. We never saw much of him dwelling on the consequences of what he did, wondering how terrible Connor's childhood had been for example and if only I had done this differently etc, it came across as mostly being about how Wesley had been wronged by his friends