I am hijacking this a bit and it will probably be long because I have a bit of a passion for this haha.
If you're not ready to make your own raw, cause it can be kind of intense/expensive, there are some amazing brands that do it for you.

I, personally, like using Primal for my dog. Primal/Stella and Chewy's is nice because they have different proteins that are great for intolerances/allergies like rabbit, quail, etc. But I believe they include Squash and Pumpkin, so I would probably avoid. But Steve's Real Food, Tuckers, and Vital Essentials are also great, and I think some formulas avoid those foods as well. (Just look at the labels of course)

I would also look into goat's milk, frozen or not. It's great for animals in general, but especially if they have tummy issues or you're trying to transition them to something new.

Also, I definitely agree with talking to your vet, but I would also try out a nutritionist.