"Matrix is an open source project that publishes the Matrix open standard for secure, decentralized, real-time communication"
I mainly use this for element so I can chat with my friends without supporting evil/privacy disrespecting companies. Though I did have to make a discord bridge (⌣_⌣”).
If you are looking to get element you can get it here. (They have pretty bad marketing right now). There are also many other clients, for example if you like WeeChat you can use that.