Got it, perhaps I crossed the streams while linking to that other thread.
I have a i3-8100 processor, definitely not Rocket Lake, but have the same experience where plexmediaserver-1.22.0.4163-d8c4875dd.x86_64 works beautifully with hardware accelerated tone mapping, and later builds don’t.
This version seems to be mentioned all over the Plex forums, lots of examples here: 4K HDR HEVC HW transcoding is broken on 1.22.1.4200 - #32 by ChuckPa
Is this still considered a regression that Plex engineering is working on? Are there any known fixes for the issue or should I just stay on the older version?