It can't be connected for a number of reasons, but the biggest is that to connect it all you have to have someone with enough ego, talent, and most importantly backing from the company, to make everybody play off the same sheet music. And WB/DC completely lack any person like that. They were HOPING Snyder could be that, but then they realized he's a one trick pony and that trick only really works for Batman movies....
And as much as you want them to take it "seriously" let's be honest, so far most of the enjoyably entertaining stuff they've put out has NOT been "serious". Shazam? Aquaman (stupid, but very entertaining), and lest we not forget the pinnace of weird and not taking itself too seriously.. Doom Patrol. (If you haven't watched that yet, SHAME ON YOU GO NOW AND WATCH BEFORE SCROLLING FURTHER!) The only outlier here is Joker and it was just a perfect damn "art piece" of a hard watch because they got the perfect guy in the lead role. I'll give that the Ledger joker made the second of the Nolan films, but the first and last left me kinda empty....
Right now I think they realize they got a charismatic guy as the main character and they can pretty easily trope it up to be a vehicle for a lot of jokes. And I'm perfectly OK with that.
