I am very doubtful in terms of head to head because Bayern Munich is too strong for Arsenal, is it possible that Mikel Arteta will give resistance to Bayern Munich, with the tactics he has because Arsenal is not that strong to face Bayern Munich, it is likely that he will have difficulties when playing at home Bayern Munich, we know that the Allianz Arena is a scary home for the clubs that play there, so it is not surprising that every club will experience defeat there.
Taking into account the fact that Bayern is far from what it was before, I would say that the chances are approximately equal. At least in London, Arsenal will be the favorite, and in Munich, Bayern. Historically, Bayern has priority, but as you know, it is not history that plays on the field, but the players. If we think strictly logically without paying attention to brands, then I would say that Arsenal looks like an easy choice to bet on, because this season they are more stable and have not had any obvious failures, while Bayern had all these problems and continues to have them.