So it's clear to me that for some reason game studios are calibrating or developing for two different HDR standards or something. I say this because games on the same console, even across consoles, using the same TV input and settings, vary in their HDR implementations. This isn't just a case of being good or bad implementations, but that the brightness/gamma is completely off in some of them. They aren't being fixed or acknowledged as a problem. The issue is the same on both X1X and PS4Pro. It's possible this is just a KS8000 problem but if so, I'm not sure why some games behave as expected and others don't.
On the KS8000, provided your TV is configured properly, in Game Mode you have to manually bump the backlight to 20 and Smart LED to high when playing an HDR title. This is expected. This adjustment is adequate and results in a nice image for some titles. Examples:
Gears 4 (X)
Halo 3 (X)
Horizon (Pro)
Insects Demo (X)
On the other hand, there are many titles where this will result in a dim, dull image. It's so far off the mark it can't be a simple mistake.
Elder Scrolls Online (X and Pro)
Everybody's Golf (Pro)
The best way to deal with these titles is to perform these additional adjustments:
Contrast to 100
Dynamic Contrast to Low or Med (varies)
Gamma to +1 or +2 (varies)
Color Space to Native
After making these adjustments, these games can look great, but the question is WHY we have to make these adjustments. Why does there seem to be two output targets for HDR gaming? Are some of these games targeting Dolby Vision and others HDR10? I wish someone would investigate this discrepancy. Even after they fix the Samsung issue where Game mode doesn't save an HDR settings profile, we will still have to go in and fiddle with settings on a per-game basis because of this.
My assumption is no on the Dolby Vision, the requirements are much more stringent for accuracy and color reproduction than HDR10.
It also costs money to license, which is probably the bigger hurdle for DV support.