I need my Roku ultra (2020 version) to do 4k60 with HDR at 8bit 4.2.0 subsampling but it seems like it will either try:
My receiver is not happy with that bitrate. I'm able to do 4k60 hdr 8bit 420 successfully with other streaming devices and I am hoping I could achieve this with the roku ultra as well.
Roku Ultra (4800 series)
Verify that your AVR's HDMI port/passthrough mode settings are configured correctly (specific to every AVR..)
There is also the option of directly connecting it to your TV (or other display device)...
(assuming you dont want to replace your receiver...)