Photos not updating

After having no issues with Photos, iCloud Photo Library and Photo Stream before that for the last 2-3 years, over the last 2 weeks the Photos app on my computer has stopped downloading Photos. Photos taken with our iPhones are uploading to iCloud, and then syncing to the other phone, but the photos are not downloading to our Mac. When I scroll to the bottom of the Photo Library, I just seen the old image counts from 2 weeks ago..."XXXXX Photos, XXXXX Videos" but no status line below that - not even the dreaded "Updating..." status.

I found this article that gave me hope. I never tried this before, but here's the relevant suggestion:

You can check for specific problems in your library with two smart albums - file menu ==> new smart album

1 - Photo - is - referenced

2 - Photo - is - unable to upload to iCloud Photo Library

these two smart albums should both be empty

Both of those smart albums ARE empty. I'm running High Sierra version 10.13.6 (17G65)

Here's what my status looks like:

Any assistance on this would be truly appreciated!