Photos on Mac Keeps getting stuck uploading to iCloud

I tried uploading my library of 20,000 photos from my Mac to iCloud, and it got all the way down to 600-something and got stuck. After a few days, I called Apple support, and I deleted all the photos from iCloud, and started the process again.

Unfortunately, it got stuck at the same number the second time. This time, support had me run the Photo Repair Tool. I once again deleted all photos from iCloud and started the process over. This time, it's also stuck in the 600s at 644.

I decided to go to the earliest photo on the cloud and then find it on Photos on the Macbook. The three that came before it were old AVI videos with no sound, so I removed those from the library, restarted my computer, and started up the sync again. It immediately uploaded 10 pictures and got stuck again.

When I create a Smart Folder and select "photos that can not be uploaded to iCloud" it shows 0 problem photos, but it even said that before I removed those silent videos. I don't know what else to do at this point.