That sounds more like Windows discovering or dropping off a HDMI connection which can result in a short black screen due to Windows. I get that if i plug in my VR headset, this monitor will go to black then come back again, that includes at the Windows desktop. The buggy black screen within games with VRR enabled is a very short blip of a black screen and noticeably different to the HDMI behaviour.All I know is that when using only DP I don't have the issue, if I mix it up again I get black screens randomly.
I only have the DP connected on the monitor and unless the VR headset is in use that is always unplugged from my system.
Not saying 100% the above is the case but mentioning it all the same.