I second the other sibling comment that recommends IRC, Matrix, XMPP. Discord is a walled garden and many people who want to avoid walled gardens are never goin

I second the other sibling comment that recommends IRC, Matrix, XMPP. Discord is a walled garden and many people who want to avoid walled gardens are never going to sign up on Discord. But something based on open protocol like the sibling recommendation is more likely to see more users.