Rikudou

Hmm, didn't seem that way, I specifically did it the way I describe in the article to have it easily reversible, though I must admit it's just theoretical, I haven't tried uninstalling it.

I still recommend my article, it's really similar on all Linux distros and Home Manager makes it much more pleasant to use.

That sounds like a nice exercise for yourself, but I don't really see it competing with other privacy-focused or open source social media (which there are already many, you might want to drop the clickbaity "first-ever" bit from the title).

As already mentioned, you can provision a Mastodon server and either disable federation or even have it enabled and you instantly can see posts/comments from other servers as well.