Interception by a third party is highly unlike, as the transport layer of basically everything is encrypted nowadays. What is left unknown is what can Meta do once the file is on their servers, as you’ll have to trust Zuckk’s word and Zuckk’s encryption
But the Signal people also say the e2e is trustworthy, no (Whatsapp, I mean)?
If Meta would really not know your Messages and encryption Keys, they would not be able to recover Every single one oft your messages even if you forgot your Password.
It’s end to end encrypted so they can’t see it then. What they could do is access it once it’s on your device and unencrypted potentially.