You are right. It’s impossible for your transmitted encrypted information to be intercepted and decrypted.
Want to buy a bridge?
SIGH. If you think that anyone can intercept and 256 bit AES standard encryption and decipher it, I'll sell YOU the bridge, Okie. Any passcode on an Apple device is entangled with the device's UUID to construct the encryption key. If any person or agency intercepting the data doesn't have the key, which at the point of transmission could be as long as 2,176 bits or as short as 160, plus stop bits between eight bit bytes, the only way to break the cypher is brute force.
If the user has selected a 16 character passcode (and Apple allows a user to construct a passcode from all 223 character accessible from the keyboard), the number of years it would take using a supercomputer capable of trying two trillion passcodes a year to try all possible keys is 5.26 vigintillion years (yes, Okie, that is a real number, it's 5.26 x 10195). My math is correct, I've done it several times to show others like you who think they could break such a cypher next week with the fancy gaming rig.
If you increase the speed of your supercomputer by a trillion, you only drop the number of years to ~5 x 10183 years. In any case, by the time they cracked your encryption, the Electrons in the Universe would have died from entropic heat death and nobody would be around to be interested in what you had stuffed in your bits and bytes which would have long since randomized and died along with the rest of the universe.
So, Okie, I can get you a great deal on the Brooklyn Bridge. . .