Blitzo is weird like that. I think the issue is we don’t have a real good picture of who he is outside of work. Like he dotes on his adopted daughter, and he stalks M&M when they’re off, and sometimes fucks Stolas to keep access to the book, but we don’t know what motivates him beyond a fear of being alone.
His relationship with Stolas is a whole other thing, where Stolas patronizes him in practically every interaction. I don’t see how it transitions to anything healthy. I’m not even sure if Stolas being a bit more friendly in the last episode is a genuine attempt at trying to build a better relationship or if he just acted that way because he was lonely.
Even if they patch things up, their relationship will always be the demon prince who’s fucking an imp. Doesn’t matter if it makes them happy, that difference in status will always be there.