Now you have a mostly working system, can you share the debug logs.
Note: I don’t have any whitelists/etc on my Alder Lake for 4K HDR playback (LG tv)
usual suggestions to test - nothing between your TV and PC - no AVR…. Compliant HDMI cable…
Jumping ahead - I have begun testing the “xe” driver versus the “i915” driver which requires an edit to the /flash/syslinux.cfg APPEND line - in my case i915.force_probe=!4626 xe.force_probe=4626 - not saying that this is a fix, but is where Intel are investing time in for the modern iGPU driver. You will need your VGA cards PCIid if you are testing this.