Got myself a PS4 Pro and it's a big improvement in most games. Soul Calibur 6 actually looks decent and Nier Automata is actually playable instead of humanoid hatchmarks running around. Horizon looks great and the image quality of Days Gone is amazing.
It's not all roses though. FF7R still has fuzzy hair around Cloud, and Uncharted still looks like a splotchy disaster. :( Gonna continue to fiddle with the settings.
It's been a long time, but I remember Uncharted 4 being pretty disappointing in terms of image clarity on Pro (even though obviously other details of the image are phenomenal).
I've noticed that whenever you have anything that resembles thin 'blades' or details like grass or Cloud's hair when checkerboard rendering is involved (Dragon Quest XI also suffered greatly on Pro when it comes to the grass, and I loved that game), you're likely going to get artifacting, artificial smoothing, etc., depending on your display. I think RDR2 had a lot of that too on Pro.
And if your TV has issues resolving those details or it's trying to clean up the image via its own processing, that can make the image even worse. Others here will have more technical responses (and have already chimed in), but you should try some native 4K 60fps games like Rez Infinite or Tetris Effect! The latter is particularly beautiful and really shows off retina-searing HDR on even middling displays. :)