Nope - the “workaround” that some places mention, as in keep your ATV4K in Dolby Vision mode all the time (bad idea!) is not actually a workaround.
The only way I have been able to properly view the Dolby Vision files is by:
1) Record video (of course!)
2) Goto camera roll and select videos
3) Copy videos to FILES (anywhere else, seems to convert them - not what you want)
4) Goto files and then copy wherever you want to play them (i.e. copy to a NAS or USB)
5) Play them on an NVIDIA Shield Pro (2019) inside of Kodi or Via Plex
Nothing else works for me - saw some people mention they can play using LG‘s native video player, doesn’t work for me on my GX, tells me video is unsupported, so not sure how it works for some that way.
PS. The video’s DO look stunning!