I can see that there is no resolution to this issue. I've even bought a NEW camera and replaced it, thinking it had to improve at least a little. Nope, not a bit. I've even tried to see if I can get into the old one to see if the focus can be adjusted. No luck with that either.
Anyway, my 2017 RAM 3500 has a two cameras and they are GREAT! One is for the bed and one is for the hitch. (There is even an option for a grill camera.) One of the biggest things I like about them is that I can turn either one of them on going down the road with a touch of the screen. I can check the 5th wheel hitch or the bumper hitch. Unless there is an option that I've overlooked on the Tahoe, I am very disappointed that I can't do the same with the rear camera.