Mac Photo Library sync stuck "moving items to shared library"

When macOS 13 came out, I enabled Shared library with my wife. Everything seemed to work fine at first. But I recently noticed it didn't have any of my photos from my iPhone since October 24.

• I can see these photos on my iPad, so I know they are in iCloud.
• The status at the bottom of the Library says "Moving 1,528 Items to Shared Library". The number periodically alternates back and forth between 1,528 Items and 1,585 Items, but it never makes any progress.
• My library is huge - 1.9 TB (I have a 4 TB iCloud plan), but it was already completely synced prior to the issue.
• My mac says I have "54,118 Photos, 4,359 Videos", but my iPhone says "66,644 Photos, 4,765 Videos". I'm guessing the difference is mostly from my wife's library.

Things I have tried:

• Restarting my mac.
• Updating to macOS 13.1.
• Leaving macbook open over night to see if it progresses.
• Temporarily switching from "Optimize Mac Storage" to "Download Originals to this Mac", to see if that gets the sync unstuck. It didn't (same status message), so after a while I switched back.

I have NOT tried disabling and re-enabling iCloud photos because of the massive churn with syncing my huge library. I may have to try that next though, without any other ideas.