Thanks for the link, but this isn't quite what I'm hitting - I'm not getting a degradation in picture quality after X minutes, the game mode quality just isn't quite up to snuff.
I've been playing around more and I think the Dynamic preset does the best overall balance I've found so far - it seems to err on the side of maintaining bright objects, so when global dimming kicks in it's not as harsh on mostly black screens, but it still does a good job maintaining black depth in complex pictures. You can still find patterns that will really mess with it - again, the opening text roll of Hollow Knight will have the local/global dimming going nuts - but in real use, I find it works pretty darn well, especially in a lit room. I booted up RE7 and ran around and even when I was sitting in very low light I was getting what I'd call "imperceptible" black depth (i.e. I can't see where the black ends and the TV border starts.)
I'm sure the input lag is there, but I can still wavedash in Celeste, so it doesn't seem that awful, lol.
I'd also add again that I have the Q80T, so if you go for the Q90T you'll have better local dimming than I do. I suspect the local dimming on the Q80T is tuned towards movies, where there's a "known" black space above and below the picture, whereas the Q90T seems to have more zones.
That said, ultimately this is still an LCD and not an OLED. If you really want pure black depth, you are gonna have to splurge for OLED - you can definitely see the difference loading up one of those "OLED HDR test footage" videos on YouTube. But for general purpose gaming my opinion on it has improved somewhat.
