Having trouble enabling Apple's iCloud Advanced Data Protection? Is it that you keep getting inexplicable errors or silent fails when you try? I've done some troubleshooting and found several distinct errors and their fixes, and blogged about it here: https://www.tarah.org/2023/01/27/troubleshooting-apples-icloud-advanced-data-protection/
Troubleshooting Apple’s iCloud Advanced Data Protection – Tarah Wheeler

@Tarah FWIW, I enabled ADP with only a Recovery Key, no Recovery Contact.