Only sync watched items since last sync

[Moreasan]

Each time I run the sync command, it takes around 10-20 min to finishes as I have many items that are not on Trakt. Is there an option to only sync the watched items since the last sync?

[glensc]

No

[glensc]

If not having matches is intentional, you should move those items to different Plex Library and then use exclude-libraries on such library.

Alternatively consider submitting shows or movies info to respective providers.