It seems that there are not many problems experienced by German clubs after the players play for their country. This can be seen from the results of the top 4 teams who were able to get 3 points after the international break. Only Leipzig failed to get full points. Leipzig had to lose to Wolfsbrug. Leipzig performed well, but indeed the Wolfsbrug goalkeeper performed very outstandingly. Casteels was able to make 9 brilliant saves. Currently several German teams will continue matches in the UCL.
At least for the big teams after the international break, this is not a big problem because the four teams you mentioned managed to win the match. Bayern Munich was the only one of the four teams to win the match by a narrow score, the rest managed to win by more than 2 goals. Koln had a good defense in this match and they managed to make it difficult for Bayern Munich's front line to score goals and fortunately Harry Kane managed to score a goal in the 20th minute for Bayer Munich's victory.
Wolfsburg managed to beat RB Leipzig with great difficulty and Casteels performed quite well in this match because he made many saves. Even though if you pay attention, RB Leipzig's game was much better and they created many opportunities, but because of their strong defense, it was difficult for the RB Leipzig attackers to break into Wolfsbrurg's goal.