For open source messengers, you can check whether they actually encrypt your messages and whether the server has access to your encryption keys but what about WhatsApp? Since it’s not open source, you can’t be sure that the encryption keys aren’t sent to the server, right? Has there been a case where a government was able to access WhatsApp chats without reading them from the phone itself?
Signal hasn’t been compromised. It has been reviewed and is continuing to be reviewed by tons of researchers and security personnel.
Its also important to note that its used internally by goverment organizations in the US so it has to be at least reasonably secure.
Don’t believe propaganda you read online.