>Do we have a federated Mastodon-esque system to replace Reddit yet?
Yes - it's all the sites that people link to on reddit :-P
For the record, there's something happening to all the big Social Media sites over the last few years
IRC/Freenode - dead, replaced by Libera, but not nearly as vibrant as its heyday
Twitter - dying, replaced by Mastodon, Bluesky, and Instagram, none of them really capture the magic that was twitter, Bluesky feels a lot like Google+, Mastodon is regularly policed by people demanding that people not act like it's twitter.. and Instagram is for kids...
Facebook - seems to be dying, they've blown things with their advertising model, and the automagic content moderation is/was also a fail (it either judges everyone far too harshly, or not at all), the users are heading to FB's other sites (Instagram) or Tik Tok
Reddit - dying (but is this temporary?), being replaced by Lobsters, Hacker News, maybe more
Tik Tok - facing serious regulatory challenges in Europe and the US.
It's inevitable that things will die/change, I do find it really interesting that the big ones from the last decade are all suddenly finding themselves on the outer.
One of the exceptions is YouTube, which faced serious competition from the likes of Tik Tok, but still appears to be generating content/high readership, and seems largely immune to the absolute garbage that's been uploaded over the past few years (conspiracy nuts, politics, etc)