I have the same and i think its just normal. You can see in light areas in the videos, you get the same areas on the rest of your screen. Think its way it works sadly. Also HDR im just forgetting cause its only HDR400. Normal monitor already is at 350-370 brightness. If you off HDR mode and look at those same nice HDR videos you can see they are almost the same. For HDR to work properly you need HDR1000.