Welcome!
I agree with posts above. Jackson eats Innova and does well on it. It's a very high quality food made with human-grade ingredients. I'd stick with a good that contains NO by-products, corn, wheat or soy.
I'm sorry to hear about Muffin.
We just lost a dog and it's been rough.
Also, was your dog eating puppy food for her whole life? Because puppy food, no matter the size of the dog, is supposed to only be fed to up to a year or a bit older. They have adult foods specially for small breeds. I don't think that would have been the cause of death for Muffin but is that what the vet was saying?