Wait, the city in the cinematic is not supposed to be Baldur's Gate? That makes no sense. The beginning with the guard in the tower is even a callback to how BG1 starts.
According to Sven its Yartar which is, depending on which map you look between 670 or 770 miles north of Baldurs Gate and has nothing to do with the game at all.
Well, it still has something to do with the game as allegedly the cult of the Absolute and True Souls are all around the Western Heartlands area, which includes both Yartar and Baldur's Gate and Amn and Neverwinter, etc. Which is why nearly everyone having ties to Baldur's Gate in particular seemed very off to me.