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.
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 a 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.