I also want to address that the Upper City being a scrapped thing seems to be kind of an urban legend, and I've seen certain things attached to it being spread as truth that are completely untrue (most notably, that this is where Karlach would be fixed and that the current game just defaults to her bad ending)
Act 3 is very much rushed and feels incomplete, but when Swen talked about the Upper City, he meant the ruined parts we see in the final battle, and just didn't want to spoil that that's where it'd be happening. This was clarified both by Larian early on when they addressed some of the backlash over what fans perceived as cut content, and by Swen later on during an interview, where he and another employee (Adam Smith, I think?) quickly corrected an interviewer who affirmed that the Upper City had been scrapped. I imagine some could think that they're just covering the truth up, I suppose, but the timeline of them talking about the Upper City in July only for it to be "nowhere to be seen" in August is too incredible for them not to be telling the truth. That is an insanely small time period to do a content chop of that caliber.
