When I have iPhone flat, the screen appears more washed out and brighter than normal. When I hold it vertical, it will get back to what it supposed to look like. Less washed out, better (less) brightness, and more contrast. I looked at all the settings and nothing stands out. I haven’t changed anything. I believe it has to do with one of the sensors in the notch, but not sure what settings would affect that other than auto brightness which is off.