Discord calls it a server but its really just a different term for a chat room. Discord does not allow you to host on your own infrastructure its all locked down and closed source.

They are not hosting it themselves. All infrastructure is fully controlled by Discord and they are subject to all Discord rules and decisions.

You can’t host your own Discord server

when I used IRC i used thelounge. it was great as an IRC client. ive since moved on to Matrix but if i were to go back to IRC id probably use thelounge again.