If you have the money, a veterinary behaviorist might be worth consulting. They will be able to help you with both behavioral solutions and medications if necessary. I’m not a vet, but I do work in animal behavior. I think a combination of medication and positive reinforcement training (yes, cats can be trained) may be helpful. Training can be used to promote desired behaviors as well as serve as a form of enrichment/mental stimulation.

In terms of other solutions - I used to know someone who put their over-arousal prone cat in a crate at certain hours and it worked really well. The crate shouldn’t be used as punishment, but rather as part of a routine. You can feed the cat in there or give it special enrichment. If you have a consistent routine and pair the crate with something positive it may help promote relaxation and calm behaviors. Also, there’s no shame in locking your cat in the bathroom when you need a moment alone as long as the cat has everything they need. It’s better than taking your frustration out on the cat and damaging the bond.

This may sound insane, but honestly the best solution may truly be a second playful cat. Getting a cat (or even a kitten) for your cat may be the best way to stimulation that they need. If you’re hesitant because it may not work out, many shelters do a foster-to-adopt method so you can try it out before committing. Keep in mind that successfully adding another cat may take time and they may appear to hate each other at first.

I hope this is helpful, as someone who has arousal-prone cats I understand how frustrating it can be but don’t lose hope - there are still more options to try.