[djnice]

I think you are confusing Tone Mapping on a media player with its ability to pass thru MaxCLL/FALL HDR Infoframe data from HDR video sources.

The Apple TV 4K does not do MaxCLL/FALL HDR Infoframe data passthrough.

Tone mapping is what a 4K HDR TV does with HDR video and Metadata to map such video to each 4K HDR TV’s individual display characteristics.

Even then different TV brands all go about Tone Mapping differently. So results will vary for differing combos.

I’m not seeing drastically different 4K HDR picture outputs when using say an Odroid N2 vs an Apple TV 4K (MrMC) in combo with my Panasonic GZ OLED TV.

There is a detailed post about Tone Mapping here: https://forum.kodi.tv/showthread.php?pid...pid2897271 

Ok, you are right, but the ATV clipping the HDR content above 800 nits. This is wrong.
Try with Spears & Munsil Demo. 

ATV 4K might be "wrong" in regards to video source MaxCLL/FALL HDR Infoframe data passthrough - but as I have said previously various 4K HDR TV's Tone Map differently.
It's not "One Size fits all" when we start talk 4K HDR TV Tone Mapping, especially Premium 4K HDR TV's that do their own sophisticated on the fly image analysis, prior to Tone Mapping.

Some 4K HDR TV's it seems (like my Panasonic GZ OLED), when it's doing it's own HDR Dynamic Tone Mapping.
Produces, visually to me - identical picture detail, and HDR brightness Tone mapped results when using MrMC on the ATV 4K vs CoreELEC Kodi on the ODROID N2.
Both picture output results are superb !

(tested with Spears & Munsil -2160p BT2020 10,000 nits clip)

These days you cannot simply discard one media player over another when we are talking 4K HDR.
4K HDR TV picture processing play a BIG part in picture output results as well.

And just to add to the mix - some 4K HDR Bluray's do not even include MaxCLL/FALL HDR Infoframe data, as seen here:
(PS: My GZ OLED has Panasonic's next gen. HCX Pro Intelligent processor in it vs the Panasonic UB9000's older 2018 HCX Processor)

Why Panasonic UB9000's HDR Optimiser is Such A Killer Feature (click)

W. 

I understand, but I see the ATV is clipping, and the bright details are lost even if I enabling the DTM on LG 65B8. See this picture: https://imgur.com/G3suTXN
I think this is not a wrong metadata problem. 
Do you see the details in the snowy landscape with your equipment?