Some of us are old enough to remember when those were already the enshitification stage, and would prefer to go back to usenet
I'm going to take a wild guess and assume this is how you grew up?
The bad part, of course, is that Discord is owned by one single entity and not indexed like the open web is.
IRC, simple php forums, no TLS, easy stuff. Nowadays we're full of technology and very poor content. In no way can mastodon (mentioning because it's the defacto decentralized social media) solve that problem. It's really easy to post stuff that shouldn't be posted.
On the other hand, crappy looking forums, slow internet connection, you really had to take the time to think about what to say and mainly why say it in the first place. It was more about the content than about quantity.
I keep toying with building a modern version of that using some of the existing fediverse infrastructure, but I just don't have the time or attention span for it. Partially because my attention span was fried by Instagram.
Even decentralized mastodon is too big and it makes it far too easy to post BS and hateful / unhealthy stuff. Plus there are far too many posts you can’t relate to or just don’t want to read („algorithm“ or not), without even mentioning the bubble effect, much worse there than on X to be honest.
Smaller communities which you can connect to /disconnect from plus a good combo of RSS feeds to get news. That’s probably it.