FC Bayern Munich

This is where you see the limitations of Nagelsmann's tactical approach, he seems to be unwilling to adapt to the players he has, and instead, plays a lot of guys out of their position.

I think for National teams this is the wrong approach, managers get very little time with their squads and very few training sessions, so it would be much more rational to just use a system that positions each player in their best role/position.

This is why most national teams play very basic 4-4-2, 4-3-3, with simple attacking and defending principles ... for a good example of how to get the best of a national team, regardless of the available players, look at Van Gaal with the Netherlands in 2010, 2014 and 2022.