Photos download from iCloud is paused

I noticed that my iPhone and iPad all displayed the same number of items in my photo library.

However, on my Mac Studio (MacOS 15.5), the photo library has paused with about 1,000 photos to go.

The library is on an external drive, properly formatted (Extended Journaling) with roughly 1.6 TB of space available.

I've gone into settings and thought if I toggled the 'download originals' it would get it 'unstuck', but that didn't work either.

Any thoughts?