Why would you want to change your messenger?
Propably your first thought what comes to your mind is the word "privacy". Good start but not the holy Gral!
It's good you started to think about it but if you realy mean it then this is a whole lot bigger process then just dropping WhatsApp. WhatsApp is capabable of sending End-to-End-Encrypted Messenges too. So this is not the biggest problem. Almost every App on your Phone harms your privacy. You agreed to it. Just becaus you did not pay with the currency money for an App does not mean you did not pay at all. Instead you pay with the currency of your data (lesser abstract: your habits, what you like and don't like, where you click on and when and what, who and when and what you speak to analyzed through algorithms because you granted the App access to your contacts, pictures, camera, microphone, etc.) which the company behind your App will use to sell to Advertiser in exchange for the currency money. It is just a different cash flow. This is the nature of a capitalistic system, so please stop moaning about it just beacause, again, you heard or read it somewhere. If you realy mean it go inform yourself, there are dozens of free (as in libre, not as in free beer) Software alternatives out there. Otherwise keep it the way you have it but do it in silence and let go the hysteric and hypocratic appall. There is nothing wrong in it but there definetly is something wrong speeking bad about the alternatives you perhaps never have tried or heard of. Although then maybe deep inside you will always be a bit concerend because of not having control of what information is known about you. You will probably always have that feeling of uncertany and questions like 'why did I just see this advertisment?' coming to your mind as well as 'what else might someone know about me, my family and childrens and the habits of us all?' Gmail is reading your mails for years now to sell your habits to advertiser. You agreed to it. In my opinion a much worse issue with instant messeaging is the social aspect of it. Everybody is entitled to their own opinion but with instant messaging those -very often- not backed up with facts opinions spread like a bad virus instantly and is drawing worng pictures and helping generating those so calles 'fake news'. This is, imo,dangerous for democracy and a healthy society. First of all not everything is automaticaly true just because it's on the Internet and some friend or family member sent you a hyperlink to something. Switch your brain on and ask yourself "Does this Link-URL look trustfully or hast it some doubios endings in it?" and if you decide that this is probably not a harmful link which won't lead to a malicious site and you decide to click on it then go on and ask yourself "who wrote this article and is it published on a trustworthy site? Could I doublecheck those 'news/informations', maybe on an international website?" in short "Who wrote it and who is the operator of the website behind it" ...to be continued