I have a similar issue. Content such as Jumanji & Downton Abbey would not play. During my anguish I tried to adjust everything however the HDR, Chroma etc settings did alter the colour to a slight degree. [Sony XBR55x800E + AppleTV 4K ...]
The solution to some of the issues was to force download a 1080m4v or mp4 file rather than the HLS video package. Not 100% but the best answer.
Once I had the 1080 video [iTunes Store] mp4/m4v... some titles would appear in a playlist but still not play until I rebooted everything, change settings and restart everything again. everything - router, hubs, switches, Mac, AppleTV, everything again and again. 4K purchased content still does not play via home sharing on the appleTV, or at least I can't get it to play unless I stream it.
To get the purchased content to play correctly (but not 4K using home sharing) I had to "remove download" and adjust settings.
In the TV app use "best available" and uncheck multichannel & HDR then download again. This allows most versions of AppleTV box to play content and use home sharing again.
You will not need to constantly change settings per movie on a movie basis, however the content will be now 1080 not 4K - but it works.