I noticed that the 12mp setting is dark indoors which should not be the case since lower megapixel should perform better in low light, but when I switched to 24 all the way to 200mp it was perfectly fine except for the 12mp unless I turned on Pro mode.
Try clearing the camera data and cache. Open settings/apps/camera/storage then clear the data and cache. It will set camera app to default but it is very easy to put back the personal preferences that were set up for it. See if that helps.
