I can't blame you, if Bayern gives priority to the defensive part during this transfer window, they will certainly find themselves better prepared for next season so they can do even better than they have done up to now.
Football, as you say, is strange, in the decisive match that could have given him the win over Paris Saint-Germain, everyone took the victory for granted, but instead Chelsea took it home.
Bayern Munich looks strong in the domestic league, and I think they will continue to dominate the league next season. However, making a few changes by bringing in a defender would add depth to the squad, making it a little easier for them to compete in the Champions League, where the competition is much tougher. Some crucial matches sometimes have unpredictable results, such as the Europa League final in previous seasons, where Leverkusen were heavily favored to win but in the end, Atalanta were able to capitalize on their potential. Similarly, in the PSG match against Chelsea, we clearly saw PSG's superiority, but in reality Chelsea emerged as the title contenders.