Wise Old Duck,
If you're trying to recover the passwords stored in your iCloud Keychain, we recommend that you try the steps here: Make your passkeys and passwords available on all your devices with iPhone and iCloud Keychain - Apple Support
To perform the recommended troubleshooting steps via the link above, complete the steps in the section titled "Recover your iCloud Keychain if all your devices are lost or stolen."
iCloud Keychain synchronization across devices provides convenience and redundancy in case you lose a single device. If all your devices are lost and you’ve added a recovery contact to your Apple ID account, your contact can help you recover your iCloud Keychain. To learn how, go to Settings
> [your name] > Password & Security, then tap “Learn more” below Add Recovery Contact.
You can also recover your iCloud Keychain through iCloud Keychain escrow, which is also protected against brute-force attacks. iCloud Keychain escrows a user’s keychain data with Apple without allowing Apple to read the passwords and other data it contains. Your keychain is encrypted using a strong passcode, and the escrow service provides a copy of the keychain only if a strict set of conditions is met.
To recover your keychain through iCloud Keychain escrow, authenticate with your Apple ID on a new device, then respond to an SMS sent to a trusted phone number. After you authenticate and respond, you must enter the device passcode. iOS, iPadOS, and macOS allow only 10 attempts to authenticate. After several failed attempts, the record is locked, and you must contact Apple Support on the Apple Support website to be granted more attempts.
The reason why we are recommending the steps above is because they will show you how to recover your iCloud Keychain.
If the resource above has nothing to do with the type of support you're seeking, provide us specifics on what you are seeing and experiencing on your end for more help, and we'll continue from there.
Thanks for using the Apple Support Communities.
Cheers!