[ztjio]

It's dark because OLED are not bright at all. Anything brighter than the filmmaker mode is modifying the source image to achieve it, or alternatively driving the pixels in a way that loses color accuracy.

If you care about film and getting the closest result to what the actual thing is supposed to look like you're going to need to couple correct settings with a light controlled room for best results. Or don't use OLED, because, it simply can't achieve the brightness of cinema projection, not even close.

Personally I like the results of a 120hz OLED so much better than other options that I strongly favor a light controlled space for movie watching. For lower grade junk it's usually easy enough to swap to another viewing preset that is brighter.