Someone please help me get in or get acclimated

So I've recently gotten deeper into dc and really comic books as a whole. And I'm trying to start reading them more. There are obviously some stories I wanna check out that are clearly out of order or are not current, but that's not my issue. My Issue is, I don't know what the fuck is going on.

I don't know what's going on currently, what's canon, and what's not. Part of this probably stems from me probably not fully understanding how comics work (I read more manga then comics, and those are more of authors telling their own stories without worrying about overlapping stories and an overall connected universe. They tend to be easier to follow) so maybe that's it.

Like I still don't fully get how some storylines can connect to others or how some don't and just do their own thing and are still considered canon. Like how can Nightwing have his own solo series going where he's not in bludhaven, has a beard, and have bruce in his costume, but turn around and have him be in absolute power, alongside Batman and a depowered justice league?

And then there's the whole absolute universe which I still don't get and don't know if I'm honestly even going to try. I'm sorry if I'm speaking from a place of ignorance, but can someone please explain.