Qwiss our bracket at 5th would've had the winners coming from: City vs Bayern and Celtic vs Madrid, or City vs Madrid and Bayern vs Celtic in the very next round. We delay that opponent to the QF.
It's less about 3rd and 5th and more about how that particular group of teams fucked around and found themselves in those specific positions. If you look at Pool for example, the table organised itself so that no good team is in their path until the semi final. And that's a bit their own doing but mainly luck.