I recently upgraded to a Gigabyte AORUS 580 in my HTPC, which is running Windows 10. I also upgraded my TV to a LG OLEDE7P, which supports various forms of HDR. The PC runs through a Yamaha RX-V681 receiver, which is set to 4K Mode 1 output. However, I'm having some major issues getting HDR to work properly. First of all, the colors are washed out on the desktop. Fine, I don't really care - would be nice to fix but whatever. At least the TV detects an HDR signal at this point. The real problem is that when HDR videos go fullscreen (Netflix, Amazon, YouTube...), the TV no longer detects the HDR signal, and the video plays in SDR (I have played the same videos from the TV's built in apps for comparison to verify that yes, it is actually not playing in HDR from the PC). Weirdly, in the Dolby Access Windows 10 app, if I move the mouse to bring up the video controls while an HDR video is playing, the TV then detects an HDR signal. As soon as the overlay disappears, the HDR signal is lost.
Windows 10 HDR toggle enabled (can't set desktop color to higher than 8 bits without this, I think)
10-bit color selected in Radeon settings (I can set as high as 12, but I don't think the TV would do anything with the higher setting)
4:2:2 chroma selected in Radeon settings (since it is an HDMI connection, I can't do 4:4:4 RGB with > 8 bit color)
HDCP reported as "Disabled" (is this bad or normal?)
Video profile in Radeon settings tested with Default and with Custom-everything turned off. Neither setting solves the issue
TV input set to "PC" (apparently this is necessary on this set to enable 4:2:2)