YouTuber Patrick-Pierre Garcia intentionally misleads the public into thinking that Dolby Vision is streamed at 12 bits. Dolby Vision is streamed at 10 bits. Also, contrary to the illustration shared in the video, nearly all commercial Dolby Vision content is mastered in P3-D65, not Rec. 2020.
“What happened is that the first HDR, the one that was created at the beginning, is a so-called basic HDR [HDR10]. Basic HDR means that it works in 10 bits. This HDR works in 10 bits with what we call a static system.”
“Another HDR has been introduced on streaming platforms and Blu-ray discs. It’s called Dolby Vision, which is part of the HDR family. Dolby Vision is very different since it works in 12 bits.”
And the channel’s got 429K subs!
The Daejeon Chronicles 
(1) It is Patrick-Pierre Garcia’s video that is exceedingly misleading
(2) HDR10, HDR10+ and Dolby Vision are all streamed in 10-bit
(3) Netflix’s guidelines are not in the least misleading. Netflix requires that HDR be mastered in 12-bit. It is streamed in 10-bit. That is quite simple to understand.
(4) Rec.2020 was developed as interchange or container primaries. It was never intended as native device primaries
I don’t know where you get all your information from, but Dolby recommends using the highest quality images as the starting point for the Dolby Vision HDR Master, with Camera RAW being best, followed by uncompressed 16 or 12 bit.