When I sync my iPhone 6s to my MacBook Pro 10.15.1, photo's don't sync and "documents & data" seem to show the phone full. After a day, chats with Apple gave up and I tried moving photos as shared albums to the cloud which worked but today my Mac shows my phone full again. The same thing just happened when I synced my wife's phone. I now deleted her photos and Catalina shows her phone full. This is not productive and I don't have much longer to live if I can't get her photos on to her phone.
I did however get her album to become a shared album on my phone……..