Connect the PVR to the receiver HDMI 2.0 input (they may not all be 2.0).
Connect the HDMI out of the receiver to the HDMI 2.0 input on the TV. They may not all be HDMI 2.0 which is required for 4k sources.
Check the PVR menu system to make sure that it is set to output in 4k and that the channel you have tuned in is 4k. It may not output 4k on all channels.
Make sure the there are no video settings on the Denon that would prevent the 4k video from getting to the TV.