WhatsApp bothers me incessantly about backing up my messages, and from a quick search online it seems like these backups are not E2E encrypted unless you go into settings and explicitly make them so, which I doubt most people do. And if they are encrypted, I would have a lot of questions about how secure those keys are and where they're stored and if they're using password managers from other tech companies, which of those companies have had NSLs requiring them to backdoor said password managers