Solving playback issues

[ArmyCW3]

I have a ROKU 4800X plugged in to a Hisense U8G.  Regardless of the app I use (Netflix/Disney+/HBOMAX/Amazon Prime) it will only output HDR and Dolby Vision content in RBG 8 bit.

The ROKU detects 4K Dolby vision. I have tried both 4:2:2 and 4:2:0. My Panasonic 4k UHD player correctly outputs 10 bit in YUV420 and other color formats so I know its not the TV

[ssijpst]

Force it to use 4K HDR TV, not Auto detect or 4K Dolby Vision TV.  I got my LG C1 to finally display 10 bit.  They don't want us to know that Dolby Vision is broke?