What is everyone feeding their Dobbie? I have an almost 2 1/2 year old on Purina Pro Plan under two chicken and rice still because when we slowly switched to adult he got sick !

I'm not the biggest fan of pro plan and have been seeing dogs get sick, I need a routine for my dog thats's affordable and fills him up. He has a sensitive stomach so I've been taking breaks in-between trying to introduce something new. He currently eats 2 cups 3x a day with the under two formula, so I'm not sure what to do now its frustrating and I don't want his stomach to hurt. He's a 106 pound Euro Doberman. I'm a healthy eater too and would love to do a little bit of a raw diet, I don't see it being a good idea for a fully raw just in case I have family watch him here and there. All his treats are all mostly fresh foods we eat together lol lots of fruits/veggies/plain versions of any meat/fish I eat.