iCloud contacts duplicate and undeletable contacts

I want to delete almost my entire Contacts database. There are many sensitive names and addresses of friends and colleagues that have passed away. The Contacts database is riddled with duplicates, individual contacts that list hundreds of other contacts information in an individual contact, and the inability to delete incorrect names and addresses. Even if I do delete them and get them to the trash it returns a -22 error code. I want to set up a new iMac that I've had for several months but I don't want it to deal with any of this nonsense. Ideas, suggestions? I truly appreciate any help provided. 😕