The first command brightens the screen and the second one returns it back to what it was. However, the “washed out” effect is still there and it’s identical before and after running the commands.
Also, using manual or automatic brightness adjustment doesn’t seem to make any difference. However, I’m not really bugged about this undesired colour banding, it’s just aestetchically unpleasing.
Since the workaround doesn’t work for some of us, there has to be more to the mystery… Could it be any help, if I uploaded the pictures before and after installing package? I used my partner’s iPhone to take the photos and they are asleep right now, so I could upload the tomorrow.