There is stoat.chat (formerly Revolt). But you wont find much help on Lemmy or Mastodon. A lot of people on the fediverse have an aversion to Discord because when they try it, they have difficulty with it like a senior citizen with a smartphone. Even though Matrix and Discord arent similar, people on the fediverse will still try to recommend you Matrix, because they think Discord is just another messenger and not like having a forum, teamspeak, jitsi and other stuff in one program. And even if you explain it like that, they will be like "but then you can just use a forum, matrix, jitsi and a screenshare program separately" or something like that.