Looks like it's been supported since October 2020: https://www.theverge.com/2020/10/3/21500399/apple-tv-youtube-4k-iphone-ipad-hdr-30-fps https://www.theverge.

Looks like it's been supported since October 2020: https://www.theverge.com/2020/10/3/21500399/apple-tv-youtube-4k-iphone-ipad-hdr-30-fps https://www.theverge.com/2020/10/3/21500399/apple-tv-youtube...