Basset hound odor

My Gussy boy stinks sooo bad. We tried the shampoo the vet gave us but it lasts 2 days and he’s back to stinking up my house lol. We thought possibly his dog food? We have him on purina pro plan, the vet said basset hounds are just know for yeast in there skin and it’s a natural odor. Any recommendations on soaps to try or foods to try? But we have to be very careful about foods because when we’ve tried to swap it really affects his coat. He doesn’t have anything wrong with his skin or anything, it’s just a natural odor, but it’s awful lol. Send help