Opened your youtube page and found that you claim you've used Nvidia Shield to do this video, in that case this is not 4K HDR, the Shield is not capable of displaying the VP9 P2 codec, which means no Youtube 4K HDR, no Stadia 4K HDR either. Hardware limitation.
BiggussDikkuss
Clickbait at best this thread.
Seriously everyone knows that anything HDR from Google requires VP9 profile 2 support.
None of the Shields support that codec for Hardware decoding.
Opened your youtube page and found that you claim you've used Nvidia Shield to do this video, in that case this is not 4K HDR, the Shield is not capable of displaying the VP9 P2 codec, which means no Youtube 4K HDR, no Stadia 4K HDR either. Hardware limitation.