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.
Julian Nagelsmann was fired by Bayern Munich when he couldn't meet the same expectations that Thomas Tuchel experienced this season, so if he returns to Bayern Munich and can't meet expectations again, I think he will receive another dismissal. So instead of experiencing disappointment a second time due to returning to Bayern Munich, it would be better if he stayed to continue coaching the German national team where he was more appreciated and his performance was quite good there. 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 don't think this is a matter of being suitable or not suitable, what makes you think young coaches are not suitable to coach the national team? I think it is each individual's choice and choosing to continue their career.
Coaching the national team also doesn't lower his standards as a great coach, he still has a lot of time and and I don't think he will continue to coach the German national team, one day he will definitely coach a big club again.