Always solve for the peace of the flock. What does it take to make your flock peaceful?
Why do you want a male? The only reason you need a rooster is if you want fertile eggs. I always try to suggest that you keep as few males as you can and still meet your goals. That's not because you are guaranteed problems with more males, just that they are more likely. I don't know if the right answer for you is one or none. That should be based on your goals.
I had a situation very much like you describe a few years back. By the way, that is not rooster, it's a cockerel. He has not totally matured into a rooster yet. That does make a difference. I had a cockerel raised in the flock. I actually do this a lot, but I've only had this issue once. As he matured he started mating some of the hens, they'd willingly squat for him. But if the dominant hen saw him mating she'd knock him off to show she was boss. This went on for a few months until he finally matured enough to stand up to her. He decided he wanted to be the dominant flock master and she was not ready to give up the position.
They fought and he won. For two days if she approached the flock he'd run her off. At times he'd just attack, trying to peck her head since that is where they can do real damage. He was not trying to mate with her, he was trying to hurt or kill her. Since there was no blood and she had plenty of room to run away I left them alone. After two days she somehow signaled to him that she accepted his authority and all problems stopped. They became best buddies.
That was a dangerous time. He could have killed her. I was watching the best I could but I wasn't down there all the time. Some hens may never give up that authority until they are dead. It's possible a rooster would not ever accept her surrender. You just don't know with animals and their behavior. I don't know what would eventually happen with yours if you keep trying.
I personally believe the girls have a lot to do with flock dynamics. I don't always blame just the boys. I have removed girls that I considered upsetting the peace and tranquility of the flock instead of the boy. If you remove the girl instead of the boy and everything is then peaceful, was it purely the boy's fault?
If your goals don't require a boy the simple solution is to get rid of him. If you want a male and also want to keep that dominant hen my suggestion is to house one of them separately for a while. Maybe as much as a month before you try again. That gives the boy more time to mature into a rooster. Mature hens are more likely to accept a mature rooster than they are an immature cockerel. That has a reasonable chance of working. But it is also possible you'll still have to make a decision between the two or continue to house them apart.
Good luck!