Thank you for responding to my plea for help, Abhishek. I've finally mananged to get the syncing on my MacBook working.
I disconnected the WiFi-Sync server on my Mac Studio as you suggested. The problem I then had was that even after restarting my MacBook, when I opened Enpass it was stuck in an endless trying-to-sync loop, ie the Synchronising wheel goes round and round and round endlessly and there's no obvious way of terminating the process.
Then I noticed out of the corner of my eye that for just a few seconds and once only a Disconnect button appeared. So I had to quit Enpass again, then watch like a hawk for a few minutes until that button reappeared. I clicked it and reset the sync. Now all is well.
I do think it would be a good idea to change the app's behaviour in the event of a failed sync in order to avoid this hassle. Anyway, I appreciate your help here.