For anyone else thinking about Matrix for public chat rooms, consider setting them up without encryption. This will remove friction for your less patient and less technical users, and may avoid frustrating glitches in some client apps.

There's not really much point in encrypting a public room anyway, so you might as well keep it simple. The client-to-server connection will still be encrypted, which is the same level of privacy that Discord has. (And you can enable encryption on a room later if you want.)