Double ratchet like Signal, but with a decentralized pool of open source relays instead of just Signal dot org really is a solid solution. That's what drew me to #simplex (the herpetic name didn't help at all). #keychat is another one that uses double ratchet; the relays are nostr relays. I'd urge caution with newer, less studied apps. Signal has gone through a lot of due diligence so far. Still, the fact you can self host is an immediate plus