I recently bought a 65'' TU7100 Crystal UHD TV. The picture is pretty good on all Apps and live TV apart from 4K and HDR programmes/films from Netflix.
The best way to describe the picture quality is washed out and grainy and is immediately noticeable as an error. HD content on Netflix is absolutely fine, and much better than HDR and 4K content. I can confirm the TV is streaming Netflix, for HDR and 4K programmes, at 15MBPS which is the maximum available (and therefore the issue is not with my internet).