The lawsuit does not provide any technical details to back up the rather sensational claims. WhatsApp's end-to-end encryption has long been a major selling point. It means that Meta can’t decrypt and read your messages; the encryption keys are only stored on the devices that send and receive the messages.
"Any claim that people's WhatsApp messages are not encrypted is categorically false and absurd,” Meta told PCMag. “WhatsApp has been end-to-end encrypted using the Signal protocol for a decade. This lawsuit is a frivolous work of fiction and we will pursue sanctions against plaintiffs’ counsel."
The lawsuit, however, accuses Meta of trying "to prevent the truth from coming out by imposing onerous nondisclosure agreements on its workers, essentially threatening the full force of one of the world’s richest companies if any of these individuals dared reveal what goes on behind closed doors at the company. These efforts have now failed, but they worked for many, many years by obscuring the truth.”
Source: https://www.pcmag.com/news/lawsuit-alleges-that-whatsapp-has-no-end-to-end-encryption