I'll probably write some of this out on AE, but I am not into incest in slash fiction. I can take stories where there's a notable age difference between a pair if the younger one of the couple is at least eighteen. I'm aware there are plenty of stories out there where the younger partner is sixteen and the older partner is in his twenties. I'm pretty sure that's illegal in most states. In original fiction, as the With or Without series progresses, Rhys was going to wait until Sterling was eighteen before starting a relationship with him. That's a "soulmates" story, too. I was happy with their decision.
I stay well away from non-con. I don't think there's anything romantic in that, though some women love that fantasy. There are a number of stories I like that have aphrodisiacs in them. These are obviously alternate worlds stories. I like those stories if both people wanted to have sex with each other anyway. I suppose I think of those as situations where the characters would have happily consented, though some people would consider fics with characters affected by aphrodisiacs as dubious consent stories. I have a problem with dubious consent contemporaries or historicals, stories set in the "real world."
I am aware that some slash fiction has little to do with real life issues for gay men. I can see why some people consider that problematic. I feel that I can judge what's closer to reality and what's not. I worry about girls who can't really make that judgment. I feel there are problems with some slash fiction, but that some is entertaining.