This is a pretty decent article and answered some of the exact questions I had when I heard about the recovered video.

or a cloud service that offers end-to-end encryption, which means not even the provider can access your footage.

That's not what "end-to-end encryption" means. End-to-end encryption means only the sender and receiver have the ability to decrypt the message. The definition the author provided would be a match for "Zero-Knowledge Encryption" instead.