yes, but that's the point: it's not a technical problem, it's an institutional problem. Facebook is pure surveillance capitalism. They live by scooping your data. E2EE is hardly a concern or a solution.
While metadata can leak a lot about conversations, it doesn't leak nearly as much as plain-text data of conversations. I've argued for years that companies have an incentive to do E2EE on private messages so they don't have to be held liable or have to get involved in a lot of investigations if they don't have any access to the info. Telegram has access to the plain-text data of the conversations, as far as I know. Signal, WhatsApp, and Messenger (more and more), seem to not have much, if any, access to the plain-text data of conversations.
But the Meta companies are lying about E2EE, I don't know? Signal has seemed to me to be the company (org actually, nonprofit) that cares the most about privacy in terms of intentions and implementation.