I still don't understand one thing. Why did Nagelsmann wanted to manage a national team already now? I mean he is a really young manager after all. He was climbing the steps really quick in his career as the last club he managed was Bayern Munich as you know.

After that I really expected him to continue managing big clubs like that.
I think national team jobs are a better fit for managers with big careers at a little old age minimum too. Because you are like a little active than being retired while managing a national team.

You are rarely playing games.
I personally don't find it strange with Nagelsmann's choice to become head coach of the national team, although indeed, I also realize what you mean because of Nagelsmann's age, of course he would still be suitable to coach other big teams otu there besides Bayern Munich. However, it seems that accepting the offer to become a national team coach will certainly allow Nagelsmann to gain greater experience. Even though Nagelsmann is the national team coach, of course there is still a chance for Nagelsmann to coach other teams in the future, just like Hansi Flick did.
Because previously Hansi Flick was the head coach of Bayern Munich and then Hansi Flick accepted an offer to become coach of the German national team, but after that, Hansi Flick returned to being the coach of another team outside the Bundesliga because Hansi Flick also accepted the offer to become head coach of Barcelona. So yes, even though Nagelsmann is the current coach of the German national team, but this does not mean that his coaching career will end with the German national team, because Nagelsmann still has the opportunity to end his tenure with the German national team and start his adventure again with new challenges in the future.