Mumble is fantastic for voice chat. Its text features are very basic, though, so people fleeing Discord would probably want something additional to handle that. Maybe Matrix.
replyA single location is a good selling point. Being able to jump into a voice chat, and still post things in a shared text chat is a good feature. Mumble should work a bit on that.
reply> Mumble should work a bit on that.
replyMumble is a labor of love, not a commercial product. I expect they would appreciate your help.