S8+ Update resulted in deleted media

I recently updated my S8+ a couple of days ago and earlier today I updated a ton of apps. Just now I am realizing that a bunch of images I had suddenly vanished. Viewing in the gallery app or through the file explorer shows that some of my albums are missing as much as 50% or more of their pictures, and a few albums no longer exist. I am assuming that all of the files not showing were deleted. I am very upset that such an update would cause a huge data loss like this, to the point that I will consider a competitor Android phone when I replace this one in a year or two. I think it has something to do with Device Maintenance, who thought it was a good idea to allow these updates to suddenly delete a ton of my downloaded images? Interestingly enough, pictures taken with my phone were not affected at all, just downloaded images. The only possible factor in me losing pictures was because of the update. No other previous updates seem to have resulted in data losses.

I do not have any cloud services running or backing data up (I don't trust those anyways) so recovering my pictures is a crapshoot. I do not have an SD card installed either, but would files saved to an SD card be safe from these random deletions anyways? Phone is running Android Oreo 8.0 with Knox 3.0 if that's any help.