So far End-to-end encryption (E2EE) is considered safer because of the way it handles information and encryption. But, nothing can be said a unbreakable, but what matters is the time taken to break it.

As you must be knowing, E2EE works in a way that only the user can decrypt it with his private keys, and even the service provider cannot decrypt, because they don't know the user's private key. That is the main reason for it be said as safe.