This is NOT true. Message keys are never sent to the cloud in WhatsApp, no matter what.

You’re referring to the optional backup that requires users to opt-in. This sends an encrypted blob of all your messages to Apple/Google, and WhatsApp holds the key (but not the data) to that. Both companies would need to cooperate to read your messages, and this is OPT-IN by default.

This isn’t E2EE, but it’s opt-in by default. It also has nothing to do with the key exchange for E2EE messages.

You’re comparing WhatsApp, with all messages end-to-end encrypted and where the only way to compromise that is an opt-in cloud backup, to Telegram, where the vast majority of people (anyone using cloud chats) do not use Telegram’s encryption.

Full disclosure: I begrudgingly use WhatsApp. I really don’t like it. You’re spreading misinformation, though.