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.
Self hosting and providing a public service are two very different things.
I’ve never self hosted a discord alternative, but it doesn’t seem like it’d cost anything to just spin it up beside existing self hosted infrastructure.
Here is some advice then: Don’t run a public service until you understand the risks and are capable of protecting yourself and your users. It isn’t as simple as booting up a service for self use. By using Discord they minimised damages to users it would be worse if they lost control of Discord alternative with RCE exploits.
Users probably wouldn’t be too damaged if an IRC server with a few public channels got hacked. I realize IRC isn’t a true Discord alternative (and I realize that’s what you were picturing when you commented- I’m not debating your point). I just can’t imagine why a self hosting subreddit would need more than text chat + help bot.
You just make a few channels on existing IRC servers don’t need to host anything. I mean if you know what you are doing go for it but unless you actually do, don’t put servers on the internet for trawlers to take over.
A fediverse IRC server network sounds pretty cool tbh. #bringbackirc