Not enough space to export/backup library. How to do partial backup?

My laptop has a 220GB SSD. My Calibre library takes up 88 GB of space. Right now there’s only about 66 GB remaining space on my laptop.

I can’t completely back up my Calibre Library (using the "export your data" function).

Is there a way I can do part-by-part backups of my Calibre library? Maybe I can back up 35 GB of the books that are low-priority reading.
Just to be clear, I don't want to save just the epub/pdf/azw files, but also the metadata associated with them (e.g. comments, date added, date modified, rating, etc).

My end goal is that, one or two years from now, when I get a larger storage space (like a 2TB HDD in the disc-drive bay), I can reunite the 35GB-portion of my books that I upload to my Google Drive cloud storage space with the rest of the my calibre library (88-35=53GB) that will stay on my laptop.