Arsenal qualified last to the semifinals in UCL 2008/2009,and after that time, we have not seen them in the Champions League semifinals again. This shows how poor their participation in champions league is. It will not be different from the previous. Assuming they were given a different club and not Bayern Munich, maybe there will be hope for them.
Arsenal vs Bayern Munich will be an interesting match to watch, regardless of the current condition of the two teams of course they have different missions this season in the Champions League, Munich who are currently down in the league certainly make the Champions League as their main target to win the trophy and at the same time to show if indeed their influence and greatness does not fade in the Champions League even though they no longer dominate in the Bundesliga, Arsenal are also on a mission to get their first trophy in the Champions League and break a bad trend of ending too soon in the Champions League after previously being able to reach the final in 2006.
Both teams will of course play all out in the match, especially Arsenal which has been a club that has consistently qualified for the Champions League until 2017, but unfortunately they began to struggle to reach the Champions League zone afterwards As you said, the 2006 and 2009 seasons were Arsenal's farthest journey in the Champions League so far, And interestingly for now they have a chance to be able to surpass their journey in the past, although it was difficult because they faced Bayern Munich but I think they still have a chance to go far in the Champions League this season.