Small update: I reloaded a manual save I had right before the Iron Throne. I've been save scumming to check when I get the crash, and I can travel between the two regions so far. Haven't re fought Gortash and Ansur yet, but at this point I'm pretty convinced it was the Steel Watch Factory that broke it for me, because I killed a lot of Watchers before they could detonate previously, and purposefully let them explode on this run to try to avoid the bug. P.S Larian really needs to work on the A.I for The Gondians, because if I didn't have survival instinct on my main character, and a couple Dimension door scrolls left, all of the Gondians would have died, because they kept running right into the Steel Watch explosion radius for literally no reason.