Can't get Dolby Vision using Apple TV on Vizio TV
I got a new Vizio 4k TV and upgraded my cables to support it. My Apple TV can drive Dolby Vision direct to the TV without issue. The problem is when I connect the ATV to my Yamaha AVR i can only do HR10. Which, honestly, isn't that big of a deal, but the colors are completely washed out in HR10 and it leads me to believe something else is wrong. I already adjusted the secret 4k Mode to "1" and tried all sorts of changes with both the receiver and the TV, to no avail. All firmware is up to date, as well.
Basically, 1080P SDR looks so much better than 2160p HDR10 and i just can't figure out where I've gone wrong.
TV: Vizio 65" M656-G4 (2019 Model)
AVR: Yamaha TSR-7790BL
Content: Apple TV 4k