Different cockerels mature at different rates. I’ve had a few as young as yours mature enough that he could make a flock master and control his flock, even with older hens in it. Very few. I’ve had some take 11 or 12 months to do that. Somewhere between 7 to 9 month is more normal with mine.
Part of it depends on your hens too. Some hens will squat for practically anything in spurs (which your cockerel probably doesn’t have much yet, by the way, he’s still quite young). But many older hens expect a male to show enough maturity to be a good father for their children before they willingly submit to him. If your older hens are not beating him up anymore (that’s pretty normal with a cockerel in with older hens), well that’s a good thing. Be patient, he will grow into the role of flock master. It might be a month from now, maybe several months.
If you are looking for fertile eggs, don’t assume yours are not fertile just because you don’t see him mating. Sometimes they will surprise you. Crack a few and look for the bull’s eye. You may find he is doing more than you think.