Short answer is go to Signal here: signal.org
What to use? (Signal)
One user wrote: "If you're looking at migrating out of WhatsApp, Signal.org is a very good option. The signal app is developed under Signal Foundation which is a non-profit foundation. It is open-source and peer-reviewed. Same is not true with Telegram and other market offerings."
Happy New Year everyone
p.s. I have been testing alternatives for a long time, Signal and Wire seem to be the best two and of those Signal is the more popular . well known and I seem to think it was created by the original author of whatsapp if anyone can confirm that.