Privacy vs iCloud data backup and Apple Inc.

Hello, Can Apple/Apple Inc. still in any way or circumstance un-encrypt the data/apps that will have been stored or backed-up on/using iCloud, especially when the full end-to-end encryption tool/process is NOT used? Can the user add a password AND a 2-steps identification tool so that even Apple - and not only the third-parties or partners /partners servers and platforms - can never have any access to any data saved and stored on iCloud ? Thanks for answer.