1) Why are you using the full color range? Do you get better image quality in your monitor with this, than with the Default : "With the video player settings"?
2) How do you set the Scaling Mode (in Display / Adjust desktop size and position)? Do you leave it at the Default : Aspect ratio or you set it to "No scaling"? I've heard that setting it to "No scaling" reduces the monitor's lag.
Personally, I leave both at their defaults.
After reading your post, a few minutes ago, I've set both my monitors (see System Specs) on Dynamic range: Full (0-255). Then I rebooted and I've rotated my desktop backgrounds. I have not noticed any improvement on my displays but I admit I have observed them for way too short time. Similarly, in the past, I've set my Scaling mode to No scaling. I think I've noticed my desktop becoming a bit snappier but perhaps it was placebo.
Thanks for your eventual input on this.