Thanks for the reply. So am I misunderstanding their data security overview page?[0]
>For additional privacy and security, 14 data categories — including Health and passwords in iCloud Keychain — are end-to-end encrypted. Apple doesn't have the encryption keys for these categories, and we can't help you recover this data if you lose access to your account. The table below includes a list of data categories that are always protected by end-to-end encryption.
The table includes Messages in iCloud with the caveat that the key is stored in iCloud backups if enabled, but the e2e key is still private, no?