I've seen some strange issues with trying to turn on HDR in the Windows display preferences.
I have a Radeon RX 580. Using Windows 10 Pro 10.0.19042, AMD Radeon Software Version 21.6.1. I also tried updating to Windows 21H1 which just updates Windows to 10.0.19043. No change in behaviour.
I can select 4K 60Hz 10bpc 4:2:0 SDR but if I try to enable HDR, it switches to 30Hz 10bpc 4:4:4 HDR. While at 30Hz it doesn't show a 4:2:0 option - just RGB and 4:2:2. The AMD Software doesn't include a refresh rate option so I have to go to Windows Display Advanced Display Settings. But it won't let me select 60Hz until I disable HDR.
Once I'm at 4K 60Hz 10bpc 4:2:0 SDR, if I enable HDR, then it switches to 4K 30Hz 10bpc 4:4:4 HDR. At this time, the info in the AMD Software and the info in the Windows Display Advanced Display Settings disagrees. Windows says I'm at 4K 60Hz 10bpc 4:2:0 HDR but AMD says I'm at 4K 30Hz 10bpc 4:4:4 which matches what my display says (display also says it's receiving HDR). Windows Display Advanced display settings won't show the correct info until I close the Display Settings window and reopen it.
Can AMD create a Displays Settings dialog that does not require using the Windows dialogs? I shouldn't have to go through 5 different UIs to change these settings. It would also be nice if I could change all the settings before they are applied so I don't have to wait between every change for the display to update (like how Ubuntu does it).