Original files missing from Photos app
Recently discovered that I can't access the original files of a bunch of my photos from 2013-2014. When I try to share or edit or do anything with these photos in the Photos app I get the following message: The operation couldn’t be completed. (PHResourceDownloadRequestErrorDomain error 0.) The photos appear to be low-res preview versions and not the original full-res. I'm connected to iCloud/internet, so I see the same photos across my devices but always get the same error message no matter the device.
I assume this means the original files are missing or corrupted? This appears to be the case with all of the photos from that time period, which were taken on a digital camera then imported to Photos. The Photos Library file on the computer (Mid 2015 MacBook Pro) I originally imported them to says it's 100GB so it would appear it still has some files in it, but is there any way to view the actual files?
I already tried Repairing the Library (OPTION + COMMAND) but to no avail. I'm really confused what changed. I recently erased a bunch of old Time Machine backups from an external drive, but I wouldn't think that would affect the Photos Library, which is stored locally. But it was only after I did that that I first noticed this problem so I can't help but connect the two.
I'm running Catalina version 10.15.7 (19H114).
MacBook Pro 15″, macOS 10.15