My 48hours old o e has the same pattern on pitch black frames.
But it is very very slight on mine.
I have the local dimming set to high, and the light sensor to on.
I just tried to take a picture and my Pixel 4 XL couldn't even pick the screen up...
What have you ended up doing?
Hard to tell exactly how bad it is due to camera exposure, but it does look worse than expected. You can see gray/black uniformity in this review which don't look nearly as bad: https://www.rtings.com/tv/reviews/hisense/u7g
I would try and replace it.