I finished the movie earlier in the week. I'm not well versed in comics and whatnot, and I got no reason to believe ZS did or did not actually intend to originally release Justice League like this. Wasn't a bad movie though, certainly waaaaay better than the originally-released version.
A friend sent me this article:
https://screenrant.com/justice-league-snyder-cut-wb-ruined-marvel-compete/
And from there I also saw this:
https://screenrant.com/superman-justice-league-2-3-snyder-dceu-ending/
I don't know how true any of this is, and I'm not familiar with this website so I don't know how reputable it is, but it does give one food for thought. I'm just glad I got an explanation for those weird dreams Bruce Wayne kept having.
Yeah there were things missing, the end credits scene like you said, The Flash racing Superman, even little jokes like when Steppenwolf is kidnapping people and they tell him "I've got a family!", in the originally-released version, he asked "Why do people keep telling me that?" There's probably a bunch of things missing from the original release. Overall not a big deal though.