open-source supporters are advised to use DisplayPort for the best experience. - HDMI Forum rejects AMD’s HDMI 2.1 open-source driver

• Linux Will Soon Have Working HDMI 2.1 With AMD GPUs - just in time for HDMI 2.2 to be ready and for the exact same problem to start again.

see also

• HP and Dell disable HEVC support built into their laptops’ CPUs