Unfortunately, no matter how good the alternatives are, you are stuck with whatever is on the other end. I can't force anyone to change their main app for comms. Even if I do manage to get them to install anything else, they will realise they only use it with me and probably drop it next time they change their phone.
While I do agree whatsapp is a privacy nightmare , I also see why it won't go away anytime soon. You only need someone's phone number to contact them, you get easy media transfers although compressed to shit, it's still serviceable and it's carier independant, and most importantly free even internationaly. People even started using it for audio calls due to higher quality audio over the plain voice calls. All these reasons create the perfect mix for the average privacy-ignorant person to overlook any competitors.