Leverkusen were the winners anyway. They benefited from the red card that Munich got. However, they didn't really play with an advantage over Munich who in fact were also able to create quite a lot of chances.
The result might have been different if there was no red card at the beginning of the first half. But this is football with all its surprises, Munich must accept this result and can focus more on the Champions League and Bundesliga.
Yea, the red card affected Bayern Munich’s performance because they were worried and Leverkusen as a big team used the advantage to win the game.
The red card was early and it is a red card to an important player that have huge influence in the squad; but’s it’s not too bad because Bayern Munich’s main target is the Bundesliga title, so even if they are eliminated in this competition it’s not a big deal, Leverkusen will be very happy to have eliminated Bayern Munich because they will have the opportunity to try their best in winning the tournament.
Munich has indeed not won the DBF Cup competition for several seasons. But Munich is still the club with the most DBF Cup winners. I am not sure if Munich is also not targeting this competition, especially if you look at the squad that was fielded, I am sure Kompany is quite serious about the match. The Bundesliga may be more prestigious, but it would be extraordinary for the club to win several trophies in one season. Munich has been eliminated so they will focus on what is in front of them. The competition is still long and they have a lot to fight for.