I had two different albums that I had been collecting photos and videos in for 10 years and they suddenly disappeared. I searched in the trash, Google images and the disappeared album and found nothing.
Some times pics and videos taken in similar locations ..similar activities get merged to keep the gallery organized.. in Google photos .. tap your profile in right hand corner.. tap photo settings...tap backup then backup folders to see which folders you activated for backup see if those albums are visible
Please follow the following troubleshooting steps, which might help to solve the issue:
Turn on Show hidden system files: search and navigate to (My Files) app (My files > More Options (three vertical dots) > Settings > show hidden system files switch)
Check the trash in My Files and Gallery: My Files: My Files app > scroll down and tap on the Recycle bin > touch and hold the missing file > Restore all. Gallery: Gallery app > Menu (the three lines) > Recycle bin > Touch and hold on the image, or select the images you want > Restore
Check synced files: (Launch Samsung Cloud app > Press on Gallery > Choose Microsoft one drive if not yet synced and look for the missing images).
Restore the Gallery files backup data: Samsung Cloud app > Restore Data > Restore > Done
