Audiobook to iPhone not syncing with updates (12.23)

Yesterday, I tried to synch an audiobook from my computer (on the books app) to my iPhone. I’ve done it millions of times so I know how to do it. However, it now jams at step 2 of 4 synching and I can’t transfer my new book to my phone nor delete books from my phone.

I feel like this happened with an update, and I’m wondering if anyone else is having that problem. If you haven’t tried since the update, you might not know it’s a problem.

I don’t know if Apple is aware and if there will be a fix soon. But this is a catastrophe (for me).