Kim Min-Jae was a magnificent player last season, he played for the eventual champions and he was a great reason why they won as well because he locked the best players down very well. I am not saying this is the type of player that can go to UCL and lock Haaland and Mbappe, that "may" not happen, which it could too, but I could easily say that he is a much better defender than what Bundesliga requires and that's why I believe that they are going to be doing fine.
I believe that we are going to see him be a beast at Bayern and Tuchel will efficiently use him. He is also young as well, which means that he could play maybe like another 10 years for them as well, that should be possible and they can get the most out of him.
By bringing in Kim Min Jae, of course Bayern Munich knows very well the problems he faced last season and one of them is the defensive position. Therefore, with Kim Min Jae, it is hoped that he can strengthen Bayern Munich's defense next season. I think the bad results in the bundesliga last season must also be a priority that must be addressed so that Bayern Munich is more consistent with a strong defense because it is very unfortunate if they often get consecutive draws like last season which allowed Dortmund to catch up with the difference in points.
As for the champions league, I think that even if Bayern Munich faces other strong teams they will try to stop every attack from their key players and I think they with the current squad are quite capable of dealing with that. I think every player must be based on a more mature character so they can be more motivated not to give up under any circumstances.