P2721Q, color bit depth specification

I just got P2721Q and connected it to my RTX 3080 Ti using DP cable included with the monitor.

Now the issue is that the only color bit depth available for this monitor in Nvidia Control Panel is 8 bit. I am unable to select 10 bit even when lowering resolution and framerate, and the same goes for HDMI connection.

To be fair, nowhere in official Dell tech specifications color bit depth is specified. I was surprised by this since some third party websites listed this monitor having 10 bit panel and that is what I expected from Dell 4K monitor very similar to S2721Q, which has 10 bit panel.

So my question: is the P2721Q monitor 8 bit, 6 bits + FRC, or 10 bit? Is there an issue with included DP cable? My GPU definitely supports DP 1.2 and HDMI 2.0 required for 4K 60Hz at 10 bit.