How to move a catalog from Lightroom Mobile to Desktop?

I've been working on Lightroom mobile because I preferred the interface, but decided to switch back to Desktop for the fuller feature set.

I have a catalog in Lightroom mobile that I need to get to desktop. Yesterday I synced a catalog in Lightroom Desktop with Mobile and it looked like it was going to work - I started seeing the photos in Desktop and went to bed as it was taking a while.

Today I get to my computer and Desktop is shut off with a message about low disk space (I had 20GB free on my device and about 60GB of images in Mobile).

When I open Desktop the catalog that previously had a few images and was syncing is completely empty. No images at all.

I'm really struggling to figure out how to make this work. I've looked through the help docs but they're written pretty cryptically at times and it seems like they're aimed at syncing in the other direction - getting Desktop photos to Mobile.

I have all the RAWs for all the images I was working on in Mobile saved on my Desktop already, I really just need to sync my edit history, metadata, etc so I can export with custom names.

Appreciate your help.