E2EE isn’t really relevant, when the “ends” have the functionality, to share data with Meta directly: as “reports”, “customer support”, “assistance” (Meta AI); where a UI element is the separation.
Edit: it turns out cloud backups aren’t E2E encrypted by default… meaning: any backup data, which passes through Meta’s servers, to the cloud providers (like iCloud or Google Account), is unobscured to Meta; unless E2EE is explicitly enabled. And even then, WhatsApp’s privacy policy states: “if you use a data backup service integrated with our Services (like iCloud or Google Account), they will receive information you share with them, such as your WhatsApp messages.” So the encryption happens on the server side, meaning: Apple and Google still have full access to the content. It doesn’t matter if you, personally, refuse to use the “feature”: if the other end does, your interactions will be included in their backups.
Cross-posting my comment from the cross-posted post
