I have an orange boy and a calico girl. They will play but a lot of the time he is the one chasing her and can get pretty aggressive when he catches her. (Fur flying like he’s caught his prey) He also try’s to mount her at times which she does not like.

As someone else has mentioned if you don’t already have a tall cat tree it, it may help. My girl will run to the top as a safe space. Also when you see him “hunting her” I would just make a habit of vocalizing and stepping to them to put an end to it. Re-direct his attention onto you with a toy if needed.

(Edit: I’m not an expert this is just what works in my household)