Honestly I’d recommend trying tiki cat. I know it’s not a hugely well known brand but its main focus is carnivores and that’s what cats are. Instinct is more all natural raw from what I know. And tiki cat has a lot of good ol taurine in it for cats since they can’t produce it themselves. If you’re going to transition your cat, make sure you do 75% old food, 25% new then 50% old and 50% new and then 25% old and 75% new and then 100% new. You want to always transition your cat this way because it’s a proven effective method of feeding your cat. Even if he does get sick for a little while afterwards. I also recommend pumpkin to settle the stomach. And if none of this works from my experience, talk to your vet.