I think I may have fixed it at least for now. I went to Preferences, WiFi Sync, clicked primary. It then asked if I wanted to disconnect from icloud and use WiFi. I said yes, then closed Enpass and reopened. I then stopped WiFi sync and re selected icloud. Now it seems to sync.
I am encountering the same issue with a Mac Mini Monterey 12.0.1, Enpass version 6.7.4 (938). Date and time are automatic. calendar, notes, ect sync with ICloud fine but not Enpass. The circle under Synchronizing just keeps spinning. No way to point sync to icloud but it seems already to be trying icloud without stopping. I tried unclicking Enpass in the icloud section of system preferences but no help.