In principle yes, in practice no, as this is a statement from the WhatsApp website:
> We limit the information we share with Meta in important ways. For example, we will always protect your personal conversations with end-to-end encryption, so that neither WhatsApp nor Meta can see these private messages.
Exactly. Zuckerburg cannot directly read your convo but the app itself writing down a few key keywords of interest and sending it back to facebook / whatsapp is not out of the question. And that amount of traffic is so tiny and could be so easily mixed in with everything else.....
Assuming they're not blatantly violating the policy (which I think they've done before), it's pretty easy to weasel out of that statement by only sharing keywords from the conversation, or only sharing the info with advertisers (but not WhatsApp and Meta), or redefining what a "personal conversation" is, or carefully redefining what "end-to-end encryption" means, or ...
There's no transparency, a huge power imbalance, and terrific pressure on WhatsApp/Meta to monetize as much as possible.
> We limit the information we share with Meta in important ways. For example, we will always protect your personal conversations with end-to-end encryption, so that neither WhatsApp nor Meta can see these private messages.