Yes. I don't endorse WhatsApp. What I meant is if you chat with 15 people out of which 5 use WhatsApp, only those 5 chats are potentially readable by Meta. Because those are the only chats which will get sent to Meta servers.
So you have the benefit that the other 10 chats are not readable by Meta.
At this point I just assume Meta, Google and Apple have my number due to people storing the number on their devices. Amazon also might have it because people might have paid me via Amazon Pay (and given it access to contacts).