What's on the bag of any dog food bag if it says min. By law they have to put min. Contents. Max content they don't. You have to call to find out
That makes sense.
Yeah, you should be able to find something with a similar profile but a lower cost. But lower cost foods are lower cost because they're either cutting corners, or because they're so mass produced that they are benefitting from economy of scale (or both), and the mass produced thing isn't going to apply to kidney diets, because they're specialized. So you may have to accept that if you're not able/willing to do home cooking and you can't afford a speciality diet, and you're constrained by the kidney requirements, the commercial kibble that fits your restrictions probably isn't going to be the most stellar thing a dog has ever eaten. It is what it is.
It's like the old saying "Choose any two: good, fast, or cheap." When it comes to dog food, choose any two: convenient, affordable, or high quality. And that's even before ruling out 90%+ of options because they don't meet the phosphorus requirement.