Not all HDMI ports are created equally. Some HDMI ports on a HDMI 2.0 device maybe 1.4 only.
Check your manual. Also check your settings since some devices will configure an HDMI 2.0 port as 1.4 by default for compatibility with older devices, and this needs to be changed in settings. Unfortunately each manufacture calls the settings something different.
Which input is the N2 on and which output is your display attached to on your AVR?
Is your display HDMI 1.4 or 2.0? Same goes for its HDMI ports as with the AVR.
Which input is the AVR plugged into on the Display and is that input properly configured?
As long as the HDMI sink is HDMI 1.4 or configured that way, or any device between initial signal source and display you won’t be able to display a 4k 10bit signal.