Even though Jürgen Klopp had retired from coach to work at Red Bull, since there's no rule in football that stops a coach or a player from coming out of retirement and continues his career, Jürgen Klopp can come out of retirement and accept the offer to become Germany head coach. Yes, Jürgen Klopp got a lot of offers from league teams but he didn't accept any of the offers. It seems Jürgen Klopp isn't interested to coach any club team after he willingly left Liverpool on mutual consent. Before Germany wants to appoint Jürgen Klopp as their next coach, they aren't satisfied with Naglesmann management, so releasing him won't be a problem.
Klopp is just trending over the media, Madrid wants him, the German national team wants, i could understand how Klopp feels being wanted by everyone, he's just like that pretty girl in a class that's wanted by all cute guys

. Naglesmann is a good coach, he tried in handling the German national team but Klopp would do better, I believe so and I feel he'll consider coaching his country over a club.
Naglesmann on his own has shown interest in coaching a club. I heard that he's a serious option for Manchester United, maybe Real Madrid could consider him as an option too. He's a good manager and would handle the players well.