HI, I am finding I have exactly the same problem with not only Netflix but with the Roku home pages and menus. It's not only darker, but black text one a lighter background enhanced the text with a bright white edge. It's really not very pleasent to watch. I also get some flickering on certain still images. I have an LG OLED TV.
I have performed the factory reset and reinstalled it twice now. It's not making any difference to the washed out colours. Could you help, please. Thank you!
My situation has improved by whiching from 4K Dolby Vision HDR TV to 4K HDR TV however, the colours aren't as rich as using the LG TV Netflix app. The screen is brighter but all the colours are simply lighter.
