Telegram is a joke. They roll their own encryption, screwed it up massively on Day 1 in exactly the ways that everyone who says "don't roll your own encryption" predicted they would [0], and make snake-oil claims about their security while responding to legitimate technical criticism with conspiracy theories about how their intelocutors are all agents of the U.S. government.
Telegram requires a phone number and the server code is completely hidden away from you which does not exactly evoke trust.
Wire might be a good contender. However, last time I looked at it I wanted to stick with options I could confidently self-host and Wire looks way too complicated on that end. (The recommended way to do it is over Kubernetes which is something I don't wanna touch in production.)
What about those?