From CNET:
Regarding Dolby vision & device streamers
"
But my TV has Dolby Vision. Should I get still it? If you have an LG TV with Dolby Vision HDR and want the best image quality, I recommend using the built-in Netflix, Amazon and Vudu apps instead of the Ultra, because Dolby Vision on those TVs provides somewhat better image quality. "
Looks like I will lose some video quality unless I use the LG built in apps!??