Signal the Protocol is good, & these are good adaptations of it.

#SimpleX is what I recommend most typically among my circle. The basic idea of "2 relays, 1 per side, instead of one signal dot com for both sides of the chat" is a really easy no-cost privacy-win concept to communicate to technotypicals 🙂

How does 0xchat call privacy compare to the others? Guessing its routed through their servers

Not sure on the details. 0xChat has written about it.