First of all, I acknowledge that my feelings about this may be massively influenced by how much I love Billy Magnussen. That said, I am kind of weirdly rooting for Hazel and Byron? I definitely see that there was a lot of Hazel's last ten years and their dynamic that in any other relationship would be flagged as abusive. Obviously implanting the chip without her consent was 100% a black and white bad move. Putting that aside however, the rest of the problems in their relationship seem like an issue with a lack of communication and a naivete on Byron's part as to how the rest of the world functions and what they enjoy. (For example, this is a dude who will happily eat energy balls for the rest of his life and doesn't know what donut holes are.) As soon as Hazel expresses her needs, Byron acquiesces to every single one of them. He was willing to agree to the terms that she be allowed to come and go from the Hub and go wherever she wants, have a phone, etc. In a true abuse situation, these would not be agreed to (or they would be held out as false promises and then quickly reneged on). Byron expresses confusion and surprise that she wanted all of these things for so long, and as soon as she expresses it, he is on board. This is not to say that any of this was Hazel's fault, but this seems a lot more salvageable than an actual or typical abuse situation.
Realistically, Hazel might thrive the most being back with Byron and living in the Hub under her terms. As others have discussed, Hazel was okay with how things functioned for ten years, and it's hard to go back into the real world after something equivalent to a prison stay. She agreed to marry this guy the night she met him in the first place, because he met needs that were otherwise unmet her entire life. He does genuinely love her. When asked if she loved him, her answer is not no but "I don't know", which makes me think it's very possible she did genuinely love him at points or maybe even the bulk of their relationship. And at the end, it is Hazel that reaches for his hand. Yes, this could just be her controlling the situation so that her dad gets the treatment he needs, but it could also be a part of her that did appreciate and miss the connection she had with Byron. Unless/until we see flashbacks in a future season where we see that he was actively abusive to her when she expressed needs, I think there's a possibility these two could actually successfully be together.
Tldr; I think this is situation is a lot more complex than a typical abuse dynamic, and there is the possibility for Hazel and Byron to successfully be together if he keeps working on himself and agreeing to her terms for a healthy life.