Photos app cannot open any of my dozen or so Libraries

Problem: I am unable to open ANY of my dozen or so Photos Libraries. Photos only shows "Restoring ... 0%" for each and every one of them.

System: Mini 2024, Sonoma 15.7.2 (24G325), Photos 10.0 (770.0.172)

Abstract: I've not been able to successfully Open, Restore or Repair any of my current libraries, nor any of their backups for the last couple of weeks. I cannot think of anything that changed or happened which preceded this situation. All of the libraries are stored on an external Thunderbolt 4 connected drive running macOS Journaled Extended. The drive has never been a Time Machine destination. The libraries are not stored in iCloud Drive. None of the libraries have been an iCloud library. I do not have iCloud Photos turned on.

Things I've been doing to try and diagnose or recover from this issue below.

• With each time I write, "Restoring ... 0%" that means also that I let it sit for several hours and never did it get past 0%. Including sometimes, leaving it for 24hrs.
• A few times, a couple of days ago, I was also getting the "can't open library (3146)" error, but that hasn't come up lately.

1. Restored different libraries from weeks or months ago from Backblaze. Each of them goes directly to "Restoring ... 0%"
2. A couple of these initially would open, and be just fine. I thought I was home free.

• • But after about 5 minutes, a modal came up saying, "The Photos App needs to quit because the library is being moved, is unavailable or the data is corrupt."
  • However, the library I was using was not being moved, was still available. But I cannot say with 100% certainty that it wasn't somehow corrupted.
  • Each time this happened, the amount of time it took for that popup to appear felt almost exactly the same.

1. Opened various of my several libraries. Same "Restoring ... 0%"
2. Opened the default library in my user's ~/Pictures folder. It wouldn't even open at all due to an error.
3. Option-opened Photos and created a new Photo Library is the ~/Pictures folder.
4. This worked.
5. I opened one of my other libraries again. Same issue "Restoring ... 0%"
6. I tried to open the same library created in #3 above. Back to the same issue "Restoring ... 0%" When I open that newly created library today I get, "Photos was unable to open the library “Photos Library 2.photoslibrary”. (3142)"
7. I tried to create another new photo library in my ~/Pictures folder. Photos hung doing that at the model dialog where it was asking where I want to put/name the library. I had to force quit the app.
8. When I attempt to move either of the ~/Pictures libraries to the Trash, Finder just ping-pongs at the "Items to delete: 1" little message box and nothing happens.

During each of these times that Photos is sitting with "Restoring ... 0%", the app will still allow me to Quit it nicely.

I and also cmd+option open Photos and attempt to repair any of the photo albums. This results in the message about "Repairing" and will jump quickly to either 94% or 95% and then it gets stuck. Never changes. Photos app then goes to "Not responding" and never comes back. I've let it sit for 2-12 hours. I have to cmd+opt+esc to force quit it.

Hypotheses, based on that I just cannot see how "all of a sudden" ALL of the libraries individually became corrupted. This feels systemic.

• There is one, maybe more "corrupted" photo albums that the "system" is keeping track of and it is causing hangs on open.
• The Photos app itself has some kind of corruption
• There are cache, temporary files, or other typically non-visible data in system folders causing this issue.

I am thinking I might have to wipe the system drive and start over. I'm concerned that doing a restore from Time Machine might bring back the issues with it, and I do not look forward to manually setting up everything from scratch. I'd love to replace just the Photos app, but that doesn't seem to be possible like it is in iOS.

Please let me know your ideas for recovering from this situation.