Some of this behavior is pretty typical. While some hens and especially some pullets will squat for anything is spurs, many mature hens require a rooster behave like a responsible rooster before he is good enough to father their children or take over flock master duties. He needs to dance for them, find them food, look for danger, and keep peace in his flock. He also needs to WOW! them with the magnificence of his self-confidence and personality. That’s hard for an immature boy to do.
What I think is going on is that his hormones are still running pretty wild and he has not learned any self-control. He’s probably bigger and stronger than the hens, certainly more aggressive, and he is trying to force the older hens to accept him as flock master. The older hens, at least some of them, are having nothing to do with that. They want more than just brute force in the father of their children. He doesn’t have what it takes.
Several times I’ve removed the lead rooster before the cockerel that replaced him was mature enough to take over the flock. Normally a hen steps into that lead role until the cockerel grows up. Practically always the transition from the lead hen ruling the flock to the cockerel taking over is pretty peaceful once he matures. But one time the lead hen refused to give up her position. I saw behavior much like what you are describing, for two days the cockerel/rooster aggressively went after the lead hen, not just forcing her sexually but chasing her to peck her head or just grab her, normally around the head. After two days she accepted his dominance and they became best buddies. But that behavior only lasted two days, yours has gone on over more than two months and now a hen is dead. That’s not acceptable.
I don’t separate my cockerels from the flock. If they are broody-raised they are with the flock from hatch. If they are brooder-raised they are with the flock anywhere after 5 to 8 weeks, depending in when I integrate them. I normally put my excess cockerels in the freezer anywhere from 4 to 6 months, depending on circumstances, often freezer space. Sometimes it gets pretty dramatic down there when the cockerels hit puberty but I have lots of room. I think that helps a lot. We all do it differently.
It’s possible that your cockerel will eventually mature enough to take over flock master duties and be accepted by the entire flock. Most do mature. But some don’t. Personality traits can be inherited just like physical attributes. I really would not want that cockerel to spread his genetics in my flock. He’s too insecure and brutal even allowing for hormones.
I know he is beautiful and you may have really become attached to him. But the only reason you need a rooster is for fertile eggs. Everything else is pure personal preference. There are a lot of good roosters out there to replace him if you really want a rooster so you don’t need to put up with him. That’s my opinion. How you manage that is up to you.