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?
The EU has been trying to outlaw encryption for most of this year.
"The EU" isn't one singular person or party or state or whatever. There are some people who are trying to outlaw it but that doesn't mean that they're the majority or that it's even legal to do.