I, on the other hand, see some banding in the lower left corner, not only in the Viewer, but also in the Quick View window. And also, which might be interesting, in Affinity Photo. But the effect is really hard to see. In Windows Photos it is also visible (at 100%). The attached screenshot is from Photos at 100% (only lower left corner of the picture). I have a Radeon RX 5500 XT graphic card.
I am still on Windows 10, by the way.