I wouldn’t go so far to say that they can’t be bonded. When I first brought my male home, my female got in the room and they fought and ripped out a good bit of each other’s fur. That’s just what they do, aggression toward another is very common. Ophelia was aggressive for a bit actually, but they are bonding fine now.
An important thing to remember is that they are not only territorial or dominant because of not being fixed. Even when the other rabbit is fixed, they will still be territorial and the concept of dominance will also persist. The territorial thing is more of a “natural instinct” while the dominance has to do with personality and pecking order- something the buns will have to sort out themselves.
In the mean time, please do make sure that they cannot reach each other. If one continues to be nipped/lunged/grunted at, it could cause them to hold a grudge and become permanently distrustful of the other rabbit. And if that happens, they may never bond.
So, keep separate where they cannot physically touch, prebond in the meantime and get neutered, then wait about a month for healing and you can try bonding.
At this point, I don’t think all is lost but if you continue to let nipping/lunging/grunting ensue through the cage you may get to a point where they won’t bond.