Hi A8690,
If the feature was enabled, iCloud Keychain is the component of iCloud that would backup and store this information. Make your passkeys and passwords available on all your devices with iPhone and iCloud Keychain outlines this feature in greater detail.
From that site, this is the process by which you can recover stored iCloud Keychain data on a new device:
"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."
Regards.