It will always annoy me how Nico’s acceptance arc was undone/retconned, because not only did it come to a very satisfying conclusion where Rick should have just moved on with a different conflict at that point or not written more books, but the more I think about it, he could have actually kept the ball rolling for that arc in an interesting way that wouldn’t have retconned anything.
Think about the aftermath of the war. Nico is accepted at camp. He is hailed as a hero - and maybe it’s a little too much. Now, everyone wants to be friends with him. Everyone wants him on their team for capture the flag. Everyone wants to talk to him now, and maybe he’s socially exhausted. Maybe when he finally gets his own cabin, people start crowding outside his door so he can contact their dead friends and family members, and he’s like “get out of my swamp”. Maybe he feels like people idolize him and only want to be friends with him now because of his powers or what he did in the Titan War. That people accept him for his parentage, but don’t truly see him for who he is - but things are still a lot better than they were
If you still want Nico to have a coming out arc - have him realize it later. He still ran away/didn’t feel accepted because he was the son of Hades, not because he was gay or [insert queer identity you want to give Nico]. Now that things are finally better in his life, he’s able to sit with those feelings. He thought he felt different because he was a demigod, then because he was the son of Hades, but then he realizes maybe there really is something else. Maybe he’s afraid because he doesn’t want to lose the acceptance he has already gained and fought so hard for. He already had to deal with being the Hades kid and is in denial, not necessarily because of internalized queerphobia, but because he refuses to have to deal with another thing that makes him different.
It’s not that he isn’t accepted. He is accepted, and it’s all too much, but at the same time, he’s afraid of losing it.