I would like to say something about the sharpness slider again.
Restart PS4 Pro and set the picture settings to 1080p.
Then start RDR 2 and start playing.
Now with the PS button again to the PS4 settings and the resolution on 2160p-RGB output.
With the PS button back to the RDR 2 Game and there in the settings display, there is now a Shaprness slider. Push it all the way to the left, back to the game.
Then again to the sharpness slider and push all the way to the right. Turn off HDR
Now the game should also be sharp on the PS4.
Sorry for my bad english 🙂