Feel free to list the alternatives, I am open to exploring them currently.
Revolt.
Element Matrix
Discord (possibility of Discord to take it down if it gets a lot of heat)
Twitter (Bad for having a group)
Forums
IRC (Too difficult)
Two more suggestions: Mumble and XMPP.
Mumble is best described as "IRC with voice chat". You can self-host it, you can set up rooms and rules, it has a voice chat, but much like IRC it doesn't have a persistent message history.
XMPP is decentralized much like e-mail, doesn't really support voice chat, at most you can have a single group chat, and the selection of clients and servers is kinda ass. It also has message persistence issues.
Generally speaking, if you want your shit to be easy for others, it won't be resilient. Discord is a deathwish, Xitter is just shit for group discussions, and self hosted solutions will require effort to moderate. In a way making your shit harder to use, like XMPP, IRC or Mumble is a good thing because it filters out idiots.
I'd also avoid Matrix, Revolt and everything that bases itself on Electron, AKA the client is an entire Chrome instance. It's shitty, slow and eats up a massive amount of unnecessary resources. Revolt devs are also massive faggots.
If you want to do more retard filtering, you could set up a managed FTP server for people to get archives from, and upload them at your discretion while keeping something like an IRC instance for chatting. This is technology as old as the World Wide Web, so forcing people to do the tiniest bit of research on how to use them will help keeping the quality of the community up.