For those who make their own cat food-nutritional premix recommendations?

I have two cats, I want to start making their food at home. I got the Know Better Premix. I made their food, put in the premix as directed, my cats would barely touch it from the beginning and if one of my cats eats even the smallest amount of food with the premix added into it, she immediately spree vomits. I know the problem isn't the food I made, they've eaten bits of it without the premix with no issues.

Anyone have a premix they can recommend that has worked for a cat with a sensitive stomach?

(Also just a PSA, I've decided to make their food myself because I found pieces of plastic in their Friskies wet food, then 7 months after switching them to Tiny Tiger, I found pieces of plastic in that food as well.)