You’re right...if you read the labels of most commercial dog foods they’re filled with awful things. One of our dogs can’t handle corn...and it’s almost impossible to find a commercial kibble w/out corn (we have found a couple.) In looking for foods w/out corn, we’ve read all the labels and ingredients on most dog foods and they’re using the parts humans can’t eat to make the dog food.
As to the raw diet, one of our dogs can tolerate it, the other can’t...it gives her “the runs.” So we have a mish mash of things we feed them, including a high quality kibble w/out grains, corn, etc. and then some raw, in moderation, plus things like cottage cheese (really good for most dogs, high protein, low fat) and plain yogurt.
I do think some dogs are prone to illness (genetics do play a part) no matter what you feed them. One of ours has Cushing’s and has had mast cell tumors and various other problems throughout her life starting when she was just a pup, but she’s still alive at 9 even though she’s had numerous serious health issues. The other dog, same breed, is healthy and has never had a health problem.
We feed them good food because it does help their energy level and reduces issues w/their skin, even though it doesn’t guarantee “perfect” health.
The last dog we had was a small Pomeranian. All he ate was our table scraps and the occasional Taco Bell salad. He even liked corn on the cob but we had to hold it for him. He died of old age.
You might want to look at Flint River Ranch dog food. It is a little more expensive that off the shelf stuff but they deliver it to your door with no additional shipping charge. I have 3 very small yorkies and one just would not eat the brands I brought home. It is human grade quality and my guys are thiving on it.
I second the recommendation of Flint River Ranch.