I need to synchronize my laptop with my office machine. The SD site says "Congratulations! The Synchronize UDP Service is Active!" from both machines, same dongle, same account.
And yet I do not see my elaborate UDP library on my laptop, just a partial library.

What could be the issue?

No, only UDPs actually used in the project will take up memory, although if the same UDP is used many times that will increase the memory used.
Also if you are working on a large project it would be worth saving more regularly than usual, and also restarting the application from time to time.