@Mer__edith I encourage anyone reading this who is concerned for their privacy to begin using to a reputable service such as Signal and encourage your friends. There are a handful of other trustworthy ones, but I can only recommend Signal because that is the only one I've used, and I believe it to be the best for my purposes based on my research.
(edit: removed my poor recollection about Telegram. Not recommended.)
@binaryphile @Mer__edith
Telegram is not E2E encrypted, unless you go on a "secret chat" which most people do not do. Even then, they use their own made crypto and have no PFS (unless you concede to their definition of PFS which is "we'll change the keys every 100 messages").
Even Meta's Whatsapp is better than this, you leak all your Metadata but at least the conversations are E2E encrypted with the signal protocol.