The ‘old’ Onedrive for Business client (groove.exe) is notoriously bad at synchronizing Sharepoint Online Libraries. If you want to block Onedrive from syncing Sharepoint Online libraries, just run the following command:
Set-SPOTenantSyncClientRestriction -GrooveBlockOption "HardOptIn"
Your users will receive a message to update their client.
And they might be a bit surprised then that the new one won’t sync libraries at all (at least until the end of the year)? It’s a toss-up whether that’s better or worse than using the old client, which just syncs badly.