Yes, issue for me with hdmi 2.1 from my Samsung 8k 2018 QE65Q900R. BT.2020 and 120hz not available in hdmi 4 for ps5 hdr, but hdr rgb are available in ps5 tv signal. TV detect only BT.1886 color and picture are washed out in hdr. Samsung, do you have any solution please? Without game mode no picture at all in this source and I have the remplacement board with hdmi 2.1 on port 4 from Samsung.
My q95t is fine, the dashboard only outputs at 60hz cod works flawlessly at 120.
You need to set the game profile to performance mode in the game app menu in system settings.
If it's cod , turn off raytracing restart the game and the 120 Hz option will be enabled.