I don't think Bayern Munich's defeat against Dortmund in the Bundesliga can be used as a reference for the match against Dortmund because of the different motivations between the two teams.
While the match against Arsenal will be different, Bayern Munich has the possibility of being slightly better than what happened in the previous season in the meeting between the two and in terms of quality these two teams have almost equal strength so indeed the Bayern Munich vs Arsenal quarter-final match will be quite fierce and very interesting.
Munich's defeat in the league certainly cannot be used as a benchmark because indeed at this time Munich is no longer too focused on the league, but despite all our expectations of course the defeat to Dortmund is a bad enough result for Tuchel this season after they are 11 seasons unbeaten by Dortmund in the league, although Munich lost the game but I am personally quite sure if it will not affect their performance in the Champions League later.
As a team that is quite experienced, of course Munich knows how they rise quickly after the defeat, and Arsenal should be wary because indeed they will make Arsenal as an outlet for their defeat to Dortmund, the quality and experience of Munich in the Champions League is certainly a foundation for us to continue to believe Munich can continue to advance to the next round in the Champions League, Arsenal are in pretty onfire form in the league but still the depth of the squad they have at the moment is doubtful for me if Arsenal can talk more in the Champions League this season.