Photos not downloading latest images to macOS
Make sure that your Mac is still uploading photos. Open the photos app and then go to the word Photos (next to File and Edit in the status bar) and then click on preferences. Then go over to the iCloud tab and you'll probably see that photos are uploading but the blue bar isnt moving or present. Click on the pause iCloud Photo Library button. Wait a minute, check your connection. Then unpause it and make sure that you Mac has a power cable plugged in and the screensaver/sleep timer turned off.

It should start uploading/downloading again in amounts.

That should fix your issue. If you have tried that before and it hasnt started the process then see if you can refresh your iCloud connection by signing out and then signing back in. That usually gets things moving again.