Matrix is just a backend framework for sending and receiving. I was actually wrong about Telegram being a Matrix client. I usually just don’t use a lot of online messaging stuff though outside work so that’s my bad. Got Telegram and Element confused.

Matrix is just the one I see more trust about in the community and getting an instance up and running is easy to do.

All three are open source (Matrix, Signal, and Telegram) so you can audit their security protocols or follow people on the issues pages that are identifying security vulnerabilities, but in the end using any service that you don’t have control over is gonna make it difficult to remain truly secure.

If at any point an instance owner decides to share server data they can, which in most of these apps won’t necessarily give them access to messages if the server never loads them as plaintext, but will give them access to information about who you’re talking with and such.

If you aren’t like actively organizing or doing anything that would require absolute security in messaging all of them would probably be fine as they’re better than sending MMS or SMS, but at the end of the day you just need to be aware of who is controlling your data and who might want it.