How to Delete 100's if not 1000's of duplicates in iCloud Group Contacts??

I am repeating a question that has not been adequately answered here for at least 6 years, nor by phone. While contacts can be deleted en masse from iCloud, contact groups cannot. It would take days, if not more, to delete each one separately.

Is there a way to completely clear everything from iCloud Contacts?

Is there a way to replace (and not add to) the iCloud contacts with the contacts from my iPhone?

Am I doomed forever to either not sync Contacts, or have 1000's of duplicate Group contacts on all my devices??

Dennis