Sure, but probably the worst for community-forum style content. Links expire, information moves all over the place, no search indexing for engines, can’t view content if you aren’t in the server already, basically impossible to have discussions about anything older than the current day. It doesn’t work for a lot of use cases that reddit/lemmy do.

It's okay for private/semi-public group based chats. It's not made for public threaded discussions.

It's a horrible alternative for reddit.

Yes it is.

But it's a terrible forum app

Sure; it's just so good at being a chat app that it makes a terrible forum.

My understanding is that it can be done and with a whole host of third party tools and bots and a little legion of mods - but that's a ton of work both setup and ongoing, just to reshape Discord into the sort of format that Reddit or Kbin/Lemmy offer pretty much right out the box.

But one of the worst for everything else it tries to be or people try to use it for, like help forums. It's a black hole for information. They've taken steps to mitigate that, but it remains a half-baked solution.

Absolutely not. And in no way is it a viable replacement for Reddit. Not now. Not ever.