Opening, sharing, and managing OneDrive-stored documents directly within Microsoft Teams
Hi Colin, hope you're doing well. I’m Ian, and I’m happy to help you today.
Sync feature syncs file thru File Explorer or Finder, a short cut to OneDrive also makes the library or folder accessible from the browser version of OneDrive, the OneDrive mobile device app, and File Explorer/Finder.
The Sync option, in both OneDrive For Business and SharePoint Online, allows content in those locations to be synced to and then accessed directly from File Explorer (Windows) or Finder (MacOS). The option replaces earlier methods to map SharePoint document libraries to drives. The option is useful and popular because it means that end-users can continue to work in a familiar space.
https://support.microsoft.com/topic/sync-sharep...
For the “Add shortcut to OneDrive” feature in SharePoint, you can sync your Microsoft SharePoint files (library) to your OneDrive. You could access the SharePoint library in OneDrive directly. Also, if you use the OneDrive application, you could see the library folder in File Explorer.
Business unless the library (or a folder in it) have already been synced
https://support.microsoft.com/topic/add-shortcu...
In summary, the link option shows the links in your OneDrive area in explorer view and follows to OneDrive online while Sync loads them in a separate company section under your OneDrive client and they do not show in OneDrive online.
This is a user-to-user support forum and I am a fellow user.
I hope this helps, but please let me know if you need anything else.