I end to approach food debates with a skeptical eye.
Royal Canin is the main food I give mine, alternating with James Wellbeloved (which is not sold in the US). I also feed homecooked and some raw. I don't like relying solely on a processed food whatever the ingredients -- and just read of some research which agrees with this -- stating dogs NEED fresh food 2-3 times a week at least as snacks or an addition to dry -- fresh fruit and veg in particular.
You will find pet food gets people quite worked up; there is an enormous range of opinion on supposed 'good' and 'bad' ingredients. Very few of the arguments about 'bad' ingredients is (yet?) supported by any research I can find -- so personally, I approach dog food rating websites with a large dose of skepticism, not least as most that I have seen are done anonymously by self-appointed experts who do not make clear their expertise or knowledge of nutrition or indeed, bias (who are they? Who do they work for? Where does their knowledge come from? WHY should I trust or believe their analysis?). And of course, there's the fact that people get unbelievably wound up and emotional about what their dog eats -- an animal quite happy to eat poop from numerous species, road carrion, rotted trash, etc etc.
Wild canids are scavengers, they do not eat kelp, berries, parsley, garlic, yoghurt, salmon oil or any of the other highly trendy ingredients in costly 'good' foods. Meanwhile, the owners are buying convenience foods, eating things filled with preservatives and colourings and artifical flavours, and processed foods. And we live about 8 times as long as a dog so all that does far more long term damage to us. :lol:
For my own part, I have had excellent results for both cats and dogs with Royal Canin and many good breeders use it. I've never had a dog or a cat with digestive problems with it and have two 9 year old cats who've had RC all their lives without a single illness and which are in great health. But I am sure many other foods would produce equally good results. I just happen to like RC.
Hence my advice is just go for a good quality (non supermarket) base food that you like, or follow the advice of many nutritional experts and rotate through a couple of foods you like and ideally supplement with some fresh foods occasionally if not daily. It's not like any one food is 'the best' and there are literally dozens to choose from!
If you are inspired, there are whole cults established around homecooked or raw diets as well. :lol: