If you wonder why you are in a particular place maybe you need to ask what questions brought you there. In this case, it's
"Is there an equivalent to LiveJournal and preferably in the Fediverse?"

LiveJournal, you may recall, was a popular blog and discussion site back in the 2000s. It's still going in some form I believe and also forked to Dreamwidth Studios, though at a time that Facebook was gaining traction so a lot of science fiction fandom just went over to FB.

Because that's what I know LJ for - the SF fandom community. There were lots of us on there. And because LJ had the following:
- Personal blogging - use it as a diary
- Discussion groups - which could be public or locked
It was flexible, in a way that FB is also. You could maintain that FB operates in the same way as LJ, with its mix of a 'wall' (do people still call it that? Did they ever?) and groups which may be by local area or by interest. It's just that the demographic was very different with FB having a more generalist audience - so generalist that a significant proportion of the world's population is now on it. When did the internet become reality rather than just commenting on it? When, as EM Forster might put it, did the machine start? Around the mid-2010s I'd say.

My nephew, who is in his late 20s, tells me that people of his generation use Instagram but not FB. But you can't put long text on IG. Nor does it do groups.
That's a different discussion though, one about Pixelfed and whether it will have groups, to bring it closer to a Flickr replacement. Pixelfed I do use, and you can have up to 2,000 characters of text with a picture but people don't go there for the text. 2,000 characters is 350-400 words in English and probably similar in other languages which is ok - we're up to just over 1,800 characters now so if this were PF I'd have to be slowing down right now.

The other thing re FB, which also makes me dip into Goodreads while mainly using Storygraph for book reviewing, and look at Reddit while not really using Lemmy, is the sheer number of users which translates into niche communities. (same in Reddit. With Goodreads that is "pretty much any book in existence is on there and there are lots of reviews to look at"). You know the saying - "Build it and they will come." Well, sometimes they do and sometimes they don't. I once worked in a community centre and my main dealings with the organisation that ran it was management asking me "why don't you think the centre gets more people going there?" My main answer was, It's in the wrong place. If it was the other side of town, nearer the park and the well-heeled areas and the swimming pool, we'd get traction. But on a more run-down side of town known only for its supermarket (drive in, get groceries, drive away) it wasn't going to thrive.

Not wishing for a moment to sound negative, though. The virtue of Federation is its flexibility - for example Pixelfed is getting so many new users at the moment. If it's in the right place then build it and they will come and they will stay.