Well I assume that the end-to-end encryption is honoured, and the message is not parsed in any way at either end. I also assume that the end-to-end reference is between your phone and the phone of the intended recipient, and not between your phone and the server routing the message. I don't have access to the source so I don't have any way to prove that, but with the objections by Facebook/Whatsapp/Meta to breaking the encryption this seems to be the case.
No, the data-mining with these apps is in your list of contacts. Whatsapp takes these and builds you into a network. Its not what you say, it is who you are talking to and when. That is valuable.
When you sign up, you up load your contacts to Whatsapp. If you try to prevent it, it will insist and not work until you do. You can try to clear down your contacts and sign up without any. However, it will still take your number and look it up in the contacts of all those who have your number. It now has your name and any details your contacts have chosen to keep about you.
No, the data-mining with these apps is in your list of contacts. Whatsapp takes these and builds you into a network. Its not what you say, it is who you are talking to and when. That is valuable.
When you sign up, you up load your contacts to Whatsapp. If you try to prevent it, it will insist and not work until you do. You can try to clear down your contacts and sign up without any. However, it will still take your number and look it up in the contacts of all those who have your number. It now has your name and any details your contacts have chosen to keep about you.