> Meta still tracks analytics which isn't good for privacy, but I'm not aware of any news of them or 3rd parties reading messages without consent of one of the 1st parties? Signal is probably much better though

Correct. WhatsApp uses the Signal protocol, and there is zero evidence of them reading message contents except with the consent of one of the users involved (such as a user reporting a message for moderation purposes).

(And before anyone takes issue with that last qualifier, consent from at least one party is the bar for secure communications on any platform, Signal included. If you don't trust the person you are communicating with, no amount of encryption will protect you).

Discovering a backdoor in WhatsApp for Facebook/Meta to read messages would be a career-defining finding for a security researcher, so it's not like this is some topic nobody has ever thought to investigate.