Don't expect too much from friendly matches, because their target in the match is not the final result, but how they can play, they must also use this match to experiment with their strategy, because whatever the result is it will not affect them at all.
The level of the two clubs competing has a much different level and if this is an official match I am very sure Bayern Munich will win by a large score too. But they couldn't win this match and I'm not surprised at all, because from the start I thought this was a match that they would use as a match to maintain the touch of the players.
They did attack throughout the match, but they didn't look determined to win the match.
True, friendly matches are just for experimenting and it is too risky to bet on that matches. I personally, rarely win when betting on friendly matches, because every team never serious. If Bayern Munich are serious of course they can win and maybe with a big score, I also believe that. But considering that this match was not an important match, they did not do their best to winning.
Yes, I also avoid betting on matches that don't require them to win, one of which is a pre-season match for example, even if the match brings together two very different clubs. In fact, I personally avoid betting on competitions that are less prestigious or in other words are not a top priority for the club.
Testing strategies in a friendly match is more useful in my opinion than looking at the final score of the match. In fact, some coaches don't set any targets before the match starts and only focus on what they can do in the match. It's not uncommon for them to field players who don't have many opportunities in competitions to see their abilities in an experiment that the coach carries out.