12bit will allow Dolby Vision in MEA. Otherwise for me 10bit 4:2:2 works fine on my OLED. Albeit with a bit of faffing switching it on and off in windows, depending on game implementation (some use a nvidia driver hook so will automatically engage it). The only colour banding I see is when using PC mode on my OLED for PC HDR. If you use console icon and game HDR for PC HDR instead, no colour banding.