If you are careful with your cockerel, you should be able to break any aggression with him. My Wheaten Ameraucana cockerel born in May pecked my hand very aggressively (when I was holding one of his girls), so I immediately picked him up and walked around with him under my arm for a good couple of minutes - he hasn’t bothered me since and moves the other direction when I come in

Don’t tolerate any aggression or they will often get worse. Nip it in the bud and you should have a good chance of end up with a tolerable rooster.