Young cat overwhelms senior cat

My young cat has tons of energy. He really loves my senior kitty and is desperate to get her to play with him, but she isn’t interested in it at all. Sometimes he gets too worked up and will be rough with her to try and get her to play. With her getting old, I’m worried that he may hurt her one of these times. He tries to pounce on her which sometimes knocks her over and I feel terrible because she has arthritis, so I’m sure it hurts the poor girl.

I know that one of the obvious answers is for me to play with him more. I do play with him and try to burn his energy so he will leave her alone more. I am more so worried about him being too much for her when I am not home during the day or asleep at night since he gets extreme zoomies out of nowhere.

Is there anything I could do to get him to be less rough with her? Their relationship has definitely gotten a lot better now that he is a bit older, but he still has way too much energy for her. I don’t necessarily want to discourage him trying to play with her as long as he isn’t being rough. I’m worried that yelling at him for trying to play will affect their relationship that has finally gotten good if he thinks playing with her is bad. Though, at the same time I really want her to get some peace and not risk getting hurt.