Hey there!
I understand that bonding can be stressful and time-consuming and before you didn’t sound to into it. So I would suggest only attempting this bonding process again if you’re going to be completely in it for the long-haul. They will obviously be aggressive around their cage because they see it as “their” territory and don’t want the other bun invading their space which is why it’s absolutely necessary to ONLY let them together in completely neutral territory until you are on the verge of cementing your bond.
Piggy-backing on what Royal said, they should definitely both be spayed as this will help with a lot of issues that can complicate the bonding process. (And it very important for female buns regardless.)
You will need to start from the beginning with them. I suggest putting a towel in each cage so the other bunnys scent gets on the towel. After 24 hours flip-flop the towels into the others cage so they get used to the other scent being in “their” territory. This also helps them take some of the aggression out on the other bunny through their scent rather than the actual bunny. As in they’ll sometimes tear at and beat up the towel rather than the other bunny. So when you introduce them, the scent won’t bother them so much.
I’m curious as to the steps you took when bonding them in the tub? I wonder if maybe you weren’t as informed about it and maybe they were fighting over something that could be fixed? Could you possibly give me details of the bath-tub session if you don’t mind and of course remember? I know it was foreverrrr ago!