I know you might mean well because giving cats vegan diets with enzymes appears to reduce animal suffering, but consider for a moment that cats cannot speak to us. Cats are proficient at hiding their pain, and they cannot tell us if their vegan diet is making them ill.

The best thing you can do to reduce animal suffering as a vegan is not to have children. Creating fewer humans objectively decreases consumption, ethical and unethical. Have a cat, eat meat, do whatever you want, but nothing will have a greater impact on this planet than to help lower its population. Heck, even murder reduces animal suffering if you don't consider humans an animal.

I'm just saying that vegan cat food is very far down on the list of effective vegan practices, and it is certainly not ethical because you cannot determine the magnitude of harm it can cause your cat.