At least according to Meta's marketing, WhatsApp is E2E encrypted. And they make ads just for this -- you can literally see billboards in NYC that advertises the encrypted messaging part of the product. It would completely destroy WhatsApp and Meta's brand if there is a backdoor somewhere. Well, Meta is never a great company to begin with, but nobody would ever lie about it and destroy their brand this way.
And I truly believe Meta has an incentive to do so. They had to reveal a conversation on Facebook Messenger on the topic of abortion after the police asked for it, which resulted in someone put in jail. Regardless of Meta's (or rather Zuck's) ever changing political position, they don't want to have liability over anything like this. They want to walk away and just say to the cops, look it's all encrypted, there's nothing we can share with you.
Better keep conspiracy theories to yourself. It's ok to question things, but better back that up with evidence.