Yeah, they need 3 goals, not even to win the game, but to level the scoreline and prolly take the game to extra time, City have to completely go to sleep for that to happen, and that's not something that happens quite often. City are known for scoring quite a lot of goals, and it is difficult to outscore them, even more by a large margin. The odds are completely in City's favor, if Bayern come into that game all flying forward looking for goals, it leaves gaps in their defense, and City are good at exploiting such, if Bayern are patient to wait for their time, City would be content with that as they already have a huge lead, i cannot see a way back for Bayern Munich.
It will be a tough tie to turn by Bayern Munich considering how they play last time out but I won’t rule out that possibility. This Bayern team actually had more possession than the City team something that rarely happens against a Pep team and that is like a way out for them. Keep the ball and frustrate city defensively they don’t really know how to defend much and a goal might come on. Get two in the first half. Pep could actually go in for a lots of rotation with players like Debruyne sitting it out and should he do this I think Bayern could have a less problem on their hands. The last thing could actually be how Tuchel set out is team because just as you have mentioned should he set this team like the last time he will get a whopping. I will prefer him to play a 3 at the back. Upamecano Deligt and Pavard. Then have Both Cancelo and Davies as full backs to help both midfield and defense. Choupo moting should be starting ahead of Gnabry because he possesses an aerial advantage than Gnabry.