or out of date. read the terms of use for business accounts, which are everywhere now. it clearly says that metabook have access to any message exchanged with a business account on whatsbook.
...and I'm not sure about groups. there are data leaks for media in groups that were dismissed as features a while ago, not just metadata. well, i think they called media ids that identify content as metadata or something. not following whatsbook closely lately.
For someone who is "not following whatsbook closely lately" that is again a bold claim to make.
But anyway, business messages are also encrypted. Businesses are allowed to designate other accounts to receive messages, in which case those other accounts are sent copies of those messages using a different key. It's similar to sending messages to multiple devices. This is disclosed [1] and needed to support things like auto responders.
Group chats are also encrypted using a shared sender key and this is described in the whitepaper starting page 10 [2]
1 - https://faq.whatsapp.com/567302067179554/?locale=en_US 2 - https://www.whatsapp.com/security/WhatsApp-Security-Whitepap...