Arsenal's performance is extraordinary this season, they have improved quite drastically compared to last season, I agree with that but we also have to look at it as a whole, their good performance is only in the domestic league, in the Champions League match they are not that strong, an example of this is the match round of 16 against Porto, they escaped with great difficulty and a little luck.
Remember that FC Porto is always a threat to almost all teams because of their experience and their defensive strength in the Champions League. Arsenal did a great job to eliminate them in the round of 16 but some people are seeing it as lack of good quality since they couldn’t be able to eliminate them easily. Nevertheless, Arsenal eliminate them and qualified to the next round through penalties.
I see that Arsenal's problem is that they don't have a strong mentality/confidence when playing against top teams and that is the opposite of Bayern Munich.
If you look at the performance of the two teams, there will probably be a pretty fierce match between Arsenal and Bayern Munich, but I think that Bayern Munich's percentage of qualifying is greater than Arsenal's.
The confidence in Arsenal team is much and it is what is motivating them to push further for better opportunities. In case of Bayern Munich this season, I have been seeing what people are predicting, but I can’t say anything especially to people understanding Arsenal’s quality because of past matches results against Bayern Munich. I stand with Arsenal this season.