What is this ugly thing on my 8K TV with HDR only content?

[Coz12345678]

-I have a Samsung QN800A 8K. 
I've followed RTINGS recommended calibration settings (for SDR + HDR), to try get the best out of my TV.
-My HDR settings are here.
-I use a 4K Firestick (2020 version) and watch my movies/series through Stremio (All 4k content, both SDR and HDR!).
-I do not use any native/inbuilt Samsung apps such as Netflix, Disney+ etc.

The issue
-With HDR content, some dark scenes (as I've come to the conclusion it's dark scenes only) suddenly have this 'grey film/haze' over the scene. Then it switches back to normal.
This Video shows the issue in action!
-I usually watch content in a dark-ish room + as HDR was initially too dark (as is generally), I had to bump up ST.2084 Gamma and Contrast Enhancer (which improves darkness).

-I've looked up so many terms, from Banding, to EOTF tracking and Contract Enhancer, thinking each time that that is the cause/issue, but I find out it's not quite that.
It seems that reducing 'Local Dimming' kinda makes the 'grey film/haze' disappear, but then the scene is too dark again.

Going forward
-My TV should still be good enough for HDR content right?
I'm now at a dead end as to what else I can do.

Please can you share any insight into what the case is, what the name of said cause is, and how the hell I fix it!

Thank you, this is my last hope!

[Coz12345678]

BUMB

Is no one else facing this issue or know what I'm talking about...?

[UE75BU8500 Owner]

I don't think you're going to get detailed help here. An AV forum will be better https://www.avforums.com/forums/samsung-tvs-forum.145/

Personally, I would NEVER buy an 8K TV (just bought a 4K 75" Samsung) because there's very very little 8K material so the TV is always going to be messing about with the image to make it 'better'. I still buy 4K Blu-ray too so it's pointless.

I do like YouTube but 8K material is very limited so that's no big loss.

I've turned off/down anything that could mess with my picture although it's fair to say there's less TV motion 'effects' on my TV than the previous 2.

[Coz12345678]

ha I've asked exactly on that forum but no replies.

We bought this becuase it was a display TV in amazing discount (along w/soundbar), so as a package I guess.

[UE75BU8500 Owner]

Ah. Well, all you can do is change the picture setting (eg Game Mode etc) to see if it lessens the annoyance which looks like a feature and not a bug unfortunately of your attachments .

I turned all (AFAIK) HDR settings off as they're either too filtered (like a veil over the whole picture) or the effect of the HDR setting does something I just don't like. That's just for YouTube incidentally as for my UHD Blu-ray I've not watched enough on this set yet to assess exactly what I don't like. And I will dislike something which seems to be the norm.

I mind looking at the 8K reviews and I was put off because I'd rather the TV NOT process to death my picture especially native 4K Blu-ray.

The "Settings" button seem like a torture device nowadays.

[Coz12345678]

bumping again till I can get some technical/engineer type help from anyone on the Samsung community.
If there are no AV people here, I might just leave it once and for all...