“Our kidneys do just fine, if not already damaged from a completely different reason.”
I haven’t specifically studied it, but there is quite a bit out there regarding high protein being tough on kidneys - but probably not to the point of threatening failure (at least in otherwise healthy people).
But, I would also guess if you get it completely wrong - very high protein, low water intake, you may start to develop problems. But then again, Keto doesn’t recommend that, and neither does anyone else here...so I don’t even know why it’s being discussed.
Since your stated goal is making people healthier, don't you think you should study it specifically? If and when you do, you'll learn that many amino acids leave you with three carbon units that the body metabolizes as a fatty acids because only two carbon units can enter the Krebs cycle. When these three carbon units are broken downs as fatty acids, ketones are created that can lead to metabolic acidosis. So, yeah, high protein diets can be hard on your kidneys. Again, this has been known and taught to students of biochemistry for a long, long time.