Discord isnt open source either tho so how does that matter for the comparison?

And while yes it is a little outdated, I do recall the time before discord when people would have their own teamspeak server instead, which worked very similar to the fediverse.

You had the client and could connect to any server you had the credentials to, which each were owned and hosted by various people or groups each with their own rules and code of conduct.

There is an alternative people have used before discord came, it is called teamspeak. Is still around as well, but works more like a federated system since everyone has to set up and host their own server for people to use.