I think Manchester City vs Bayern Munich will be the toughest and most interesting fixture amongst all four games because both teams are strong and eager to win the Champions league trophy this season. I think that Bayern will try to mark Haaland aggressively since he’s City’s top scorer, but Pep will be expecting this strategy. I would like to see what strategy the managers will be playing on match day.
Bayern Munich may defend aggressively to stop Haaland from scoring goals, but I don't think it will because Haaland is very fast and sharp when it comes to scoring goals, and he also has teammates who are very smart to assist in scoring. I believe it will be very difficult for Bayern Munich to defeat Manchester city at this point, unless the Manchester city players are not in good format that day.
After all, both teams have an attacking style of play, so both of them will attack each other and not only focus on defending. But yes, guarding Haaland is a focus that must be maximized, because if Bayern Munich doesn't maximize it to keep Haaland tight, then Bayern Munich's goal is of course very vulnerable to conceding.
But I'm sure these two big teams have a good way of being able to attack, so they will have their own goals. But somehow I feel Pep Guardiola has good information about Bayern Munich, so I believe Pep Guardiola has a better strategy in this match.