No, I was referring to any resolution. Interesting that 1440p works for you at 10 bit. Were you able to apply that setting, and then check that indeed you are running at 10 bit? Sometimes the nvidia Control Panel lets you see choices that it does not support - once you click OK it will not actually switch to the selected mode.Are you referring to 4k support only? I don't have a 4k monitor, but I am able to select 10 bit at 1440p120 full RGB/YCbCr 444 in NVCP.
If it does work, does it also work for 1920x1080?
Would be useful to know what video card you are using, what type of connection: DP or HDMI, and what display too, indeed!
The reasons for this constraint are not technical, are to prevent companies from using professional software (CAD/CAM/CAE) on computers with consumer video cards.