Moving from WhatsApp to Signal is an important action, right now. WhatsApp’s parent company, Meta, has been involved in several cases of election interference: America in 2016, Trinidad and Tobago …
That’s their problem. If their messages aren’t encrypted, it isn’t like you won’t be aware of it. Request that they use a modern client and get with the times. None of this is an actual problem without easy solutions.
So much cope you didn’t even notice no one mentioned matrix. We are comparing XMPP with Signal.
Also, you really think saying only 20% of your chats are insecure is somehow making it better?
That’s their problem. If their messages aren’t encrypted, it isn’t like you won’t be aware of it. Request that they use a modern client and get with the times. None of this is an actual problem without easy solutions.