My phone doesn't see a lot of the media on it. (not a .nomdeia issue)

A

AC Question

Ok, so I've been trying to sort this issue out for almost half a year now.
All of a sudden my phone just stopped being able to 'see' all the current media on it, I initially noticed this because my ringtone changed back to a standard one, when I checked the gallery it was empty.
At first I thought it was a .nomedia file hiding everything but I couldn't find any, and when I took new photos they appeared in the gallery as if everything before them had just been deleted.
I installed a different gallery app that had the option to "view hidden files" and there it all was, but the thing that puzzled me was that the new photos and videos were in the same folders as the old ones.
Even weirder anything I downloaded couldn't be seen, literally the only media the phone would see is media it created ITSELF (photos, videos, sound recordings and screenshots).
I became curious and checked the files on the PC and the main difference was that many of the media details like photo dimensions and video duration were missing on all the old non-visible media while it was present on all the new media.
I copied a few photos and videos over to the PC, let it add it's own info to the files, checked them to make sure dimensions and durations were all there, then copied them back to the phone to see if they would show up and all the information disappeared! Which explains why I can't see new files downloaded from the internet ect.

I'm honestly at a complete loss, does anyone know what could be causing this?
Any help would be greatly appreciated!