Agree that it shouldn’t be so complicated. I see that as a major flaw of the platform that will curtail adoption, but who knows, maybe one will win out over the others?
In any case, my understanding is that you can’t log into the other instances with your username from lemmy.one, but you can read posts and interact with communities on different lemmy sites. For instance, I’m commenting from lemmy.world on a post you made using lemmy.one at a community hosted on lemmy.ml, but we can both read each other’s comments, and so can people that signed up on other instances like beehaw.org.
I almost exclusively read non-fiction, but I just got done reading Slash’s autobiography (the guitarist for Guns N’ Roses among other projects), and that book kept me absolutely hooked from start to end. I have no idea how he’s still alive after the wild stuff described in that book.
I shifted from that to a book about the history of the US Postal Service last week, so it’s a pretty big contrast in tone.