I contacted them as well. It's far beyond just turning off HDR off. I think people that think that it looks fine or even switching to 1080p with super sampling just do not understand image quality. This is completely unacceptable. I had to play on my small 28 inch 4k monitor because the image has so much noise that I can not stand looking at it.
I would recommend commenting on Twitter post from official Rockstar as well.