Ok, I am really beginning to hate this projector and just wished i dropped more on something that gives me less stress in life.
Thinking it was my cable I bought the ruipro optical 33ft. Absolutely no difference.
I have my Shield set to 4k 420 10bit > 6 ft high speed HDMI cable > Denon X2400H set to bypass > Ruipro > Vivitek 2288. I have played with every setting under the sun and all HDR content on Netflix and Kodi is washed out and worthless. I have never seen HDR in any information text on the Vivitek.
I may be on old firmware, but I thought that was only to address drop outs, I have yet to ever see HDR. SW Ver 1: MS019F, SW Ver 2: DD18, SW Ver 3: MC20
Another thing, if I connect my Shield directly to the Vivitek, there is insane lag on any video. Its like the projector cant even keep up and studders about every 2 seconds on video. It never does this when coming from the Denon....which makes 0 sense to me.