I'm sure Bayern can still put in another different performance in the Community League and it will be easy to beat them.
I don't understand what are you trying to explain, but it is not Community League. It is the UEFA Champions League, this is the highest football competition in the world. No team has a guarantee to win UCL trophy, including Bayern Munich. In the quarter-final, Bayern Munich will face Arsenal, it shouldn't be easy for Bayern Munich to beat Arsenal. If you look at the EPL standings, you must be aware that Arsenal is strong enough to challenge Bayern Munich.
You are right that no club is certain to win the UEFA Champions League trophy because of how competitive the UEFA Champions League is. It might even turn out that Real Madrid, Bayern Munich, and Manchester City, who are favorites to win this season's UEFA Champions League trophy, will not win it. That is why it is called the UEFA Champions League.
There is no definite guarantee for those who have good results in the domestic league to also get good results in the Champions League. Because sometimes teams are not in a good position in the domestic league standings, but sometimes teams like this will get good results in Champions League. Of course, any result can still happen and in any case, at this moment at least Real Madrid and Manchester City are still title contenders. But unfortunately, Real Madrid and Manchester City met in the quarter-finals and therefore, of course there is an opportunity for other teams to be able to maximize moments like this to achieve the highest achievements.
But indeed, regarding Bayern Munich who experienced bad results this season in the Bundesliga. Then maybe Bayern Munich will really maximize their efforts to get good results in the Champions League, but just about good results and not about winning a trophy becasue is certainly a difficult target for them.