I would only send it back for banding if it was really noticeable in content, some people have found it settles down a bit after some use also.
Not got much time atm but if you search the issue there are certain scenes from films and TV shows that will highlight whether it's a "real" problem for your set.
Just gave it a test in the pitch black with some youtube greyscale/banding videos and i'm really impressed! I am normally mega picky and anal about this sort of thing (sent countless LED/QLEDS, even high end ones back, because of god awful backlight behaviour/haloing/uniformity etc), but any issues with this are almost imperceptible. As you say, i'm sure its there to some degree, but the uniformity of this one seems very very good.
Good lord i love OLEDs. Its a delight when the scene/backdrop is black...and it actually goes black! Never going back to anything backlight. All the local dimming areas in the world don't fix the inherent issue with that tech.