Onyx and nothing else for social media.
Discussion
I use telegram just to send message to me, phone to PC and "vice versa", there is no app that do that sadly
Signal has “note to self”, too.
I think not yet
They have their own altcoin: https://support.signal.org/hc/en-us/articles/360057625692-In-app-Payments
I also used it very often. Now i try without