After the latest updates, it's not possible to move pictures completely to albums from gallery pictures. What it does now is COPYING pictures to new destination (album). One of the main reasons I changed from IPhone to S10+ was just the mentioned feature, MOVING pictures to albums and seeing them only there and not in gallery pitures too. By moving I could arrange my pictures in a good way and having the rest left in gallery pictures. I hope Samsung understand the problem and fix it otherwise my next phone will not be a Samsung.
I am using an M30s.
I'm not sure it is a copy but just a link to the photo in pictures. When I moved a photo to an album from pictures and then erase it in pictures it erased the one in the album too.