Actually, both Hills and Purina offer grain free foods. They just have more grain inclusive. As for the grain free issue, there are several threads with many links here on the forum that I would encourage you to take a look at. There's actually no reason dogs can't have grains. You often hear about allergies to grains, but the truth is that most allergies are due to the protein source. There are plenty of really good grain inclusive foods. Just like there are many good grain free foods. I think every person should do the research in an open minded manner and decide what they're comfortable with. I like the foods Loverboy Skyline is using. I had very good luck with them until the fat content was too high for one of my dogs. I also really like Fromm a lot. Again, it just didn't work for my one boy. I would suggest perhaps avoiding a chicken based formula as many of our dogs have a chicken allergy. (Processed, not raw.)
Here's a newer article on the grain free issue that you may find helpful.
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6396252/