To be fair, Arsenal have been one of the most consistent English Premier League teams in the past two seasons especially in their domestic league and I think it is because of the how good the club manager Mikel Arteta have been with his managerial approaches and tactics. They've gone from the Arsenal team that was always considered as an average team after Arsene Wenger left the club to become one of the most formidable English teams of the last two seasons and that's why a lot of people are tipping them to get past Bayern Munich in the quarter finals of the UEFA Champions League competition.
Bayern Munich without doubt is a better club than the Gunners in terms of quality players as well as players that are very experienced in the Champions League but Arsenal I think still have a chance to eliminate the German champions if they can play at their best in the two-legged games
I can agree with you about the performance of Arsenal in EPL. In the last 2 seasons, Arsenal always become a very competitive team, they are joining the race for the title. Now, they are leading the EPL standings although they have the same points with Liverpool. However, it is not easy to lead the EPL standings because it is the most competitive league in the world. So, if we consider the performance of Arsenal in EPL, no doubt Arsenal has a chance to beat Bayern Munich. But sometimes the performance of the team in the domestic league can't determine the performance in UCL. Bayern Munich is clear to have a better history in UCL, they already won the title many times. Bayern Munich already won 6 UCL titles. However, the current condition can be different, Bayern Munich is no longer the same as the previous Bayern Munich squad. So, I also think that Arsenal may have the chance to eliminate Bayern Munich in UCL. Moreover, the status of Arsenal is like a black horse, they are not the favorite team to win. With this status, Arsenal won't have a pressure in the match.