Hi
I think I'm having the same problem as Jaeger, above. My Kindle takes hours to update collections, and even when it says it has finished, the only collection I can see on it is the one I created on the Kindle itself earlier.
I set Librarian Sync to work at 6pm yesterday - it still hadn't finished at midnight, and when I looked this morning hadn't done anything. I've tried again now and it's been running for an hour without success.
I have a Kindle Oasis running 4.6, it's jailbroken, has KUAL installed, Librarian Sync shows up in KUAL. I have Collection Manager installed in Calibre, and after running it, it indicates that i have 465 books in 45 collections.
I'm running Python 3.8.
I'm good at following instructions

but i'm not a coder

and I didn't understand what it was you told Jaeger to do which worked

so just to warn you that I might need to ask for extra detail.
Thanks for any help you can offer.