Today I've made my decision, and I uninstalled WhatsApp. It was liberating. I wanted to do that for a long time, but some family needs prevented me to accomplish it. In place of WhatsApp I will use Telegram and Signal only.

WhatsApp just sucks. It is owned by Facebook, the second biggest advertisement company, it is closed-source (it can contain trivial backdoors in their source code which can also affect their encryption protocol) and it is very clunky to use. Every messaging app is waaay better than WhatsApp. Its only advantage is their massive user adoption, which now counts 5 billion users.

The first one is undoubtedly superior from the point of view of functionality. It's the perfect compromise between privacy and comfort. Default chats aren't end-to-end encrypted, but they only are encrypted in transit (basically, between the person and the server. The server can still view contents of messages). This system doesn't guarantee privacy from Telegram servers, but it allows server-side processing that allows unparalleled comfort. If you wanted to, you could also communicate in a end-to-end protected chat, with a cryptographic protocol that guarantees that only the two persons involved can read the message. Groups and channels cannot be end-to-end protected.

On the functionality side, Telegram is unrivalled.

Signal has less funcionalities included, because every chat is end-to-end encrypted by default. In other words, one can do less things, but the chat is more protected by default. A Signal's secondary flaw is the lack of people to communicate with, at least in Italy. At the moment, the chat has 50 millions users, against the 500 millions of Telegram. This will be solved overtime and convincing people to switch to privacy-respecting software. Many Free Software projects started from nothing and became important with the progressive adoption from people and enterprises. The important thing is to perseverate using products that actually respect people. Another Signal's flaw is that both users in a chat currently need each other's phone number, and that may be an issue if you are concerned with revealing your phone number. In Telegram, you don't need to expose your phone number to chat with other people.

That said, privacy is a compromise: only after some of my parents and important contacts switched to Telegram or Signal, I could switch in turn.