So the TV updated to 22.214.171.124.
They FINALLY allow Clear Action to be used with HDR and it works! I'm absolutely ecstatic! I've been waiting for this since the release of the TV. As you might know, this will mostly be a benefit to gamers, nothing else really.
There's good and bad.
At default, Clear Action literally does nothing but add that black frame between frames, so HDR will still yield the wider color gamut and peak brightness algorithms, so if something asks for peak highlights, adjusting the backlight won't change this.
Having tested a couple of HDR enabled games like FFXV, Ratchet and Clank, Last of Us Remastered, Wipeout Omega Collection, it was good to see that the extra details and HDR changes made to these games remained even with Clear Action on, despite the lower light output caused by CA.
Obviously, this will truncate the overall light output/maximum nits of the display, so at default, this will be dim if you've been used to 50 backlight without Clear Action, or particularly if you are in a well lit room.
HDR is 'optimal' in the Backlight 50 range, and adding backlight levels will blow out the details and generally just look bad (which has always been the case with or without Clear Action. As for the lower light output, I'm not too bothered, as I normally use the TV in SDR with Backlight 25-ish whenever I'm not using Clear Action, and Backlight 50 with Clear Action.
If you want HDR and Clear Action and want higher light output, sorry, but you do NOT wanna set backlight to high levels as, yes you'll gain a lot more general brightness, but will be destroying details. Unlike SDR where you can change backlight to whatever you want and all details will remain the same.
In the end, this won't matter to everyone who hates Clear Action to begin with, but will be a great addition to those of us who have had to choose between Clear ACtion and HDR. Now we get both, reaping the benefits of HDR changes made in games, including wider color gamut, though our general/peak brightness will be the one drawback.