I understand why you feel Bayern will win Barcelona based on past record which might still have some impact in the game. With the brilliant performance of both clubs currently, it is difficult to predict the winner because they are topping the table in their various domestic leagues. However, Barcelona is playing at home and that is an advantage form to use in winning Bayern who might find it difficult to win away from home. This might be an opportunity for Barcelona to break the spell on them that is always making Bayern win them with Hans Flick as the new manager.
I do not have a view on the analysis of the Bayern Munich coach when facing a crucial match like this and usually the Champions League will put a little pressure on each coach and facing a much more balanced team will make everything different. Moreover, Barcelona has the advantage of playing at home so their motivation will be much greater even though if you look at the quality of the Bayern Munich players they are slightly more favored.
I see a home game is Barcelona's only advantage. Their squad is not much better than their opponent's. But to call that if Bayern is being slightly favored in this game doesn't meet the reality. The latest odds still slightly favor them over Munich to win the game. And they probably get one or three points from Munich soon.
If referring to the head to head, Bayern Munich is also still the favorite but that does not mean that such an advantage can be a guarantee. I only dare to predict the match to end in a draw because in any case both teams will definitely play more carefully.
I can't really use the past result to determine the outcome in the upcoming game. Bayern looked far superior in term of head to head compared to the Barcelona, but let's not for get these things. They have different squad, coach, and staff. So, it's greatly impacting their performance against Barcelona.
They're not at their prime. I believe they'll struggle to beat Barcelona with Hansi Flick on their opponent's side.