TLDR: The r/selfhosted subreddit has a Discord server. The owner’s account got hacked leaving the server in a precarious state. They submitted a support ticket, but Discord has not taken action in weeks and probably won’t at all, so they are considering starting a new Discord server.
At least voice and video are often done peer to peer. So the strain on the server would be almost zero.
There is still transcoding done thru the server, maybe depending on the app but the ones that use livekit it would.