I don't know what Tuchel should be thanked for. This data is so clear cut that nobody should actually come to the conclusion that it was right to fire Nagelsmann based on that data alone. There might have been other reasons, but Tuchel hasn't achieved any improvement or progress at all. He achieved the opposite and almost even lost the Bundesliga title, but Dortmund came to the rescue.
We don't know why Nagelsmann was fired. But the decision to fire Nagelsmann was not correct. Bayern Munich's performance further deteriorated after the sacking of Nagelsmann. They were eliminated from the Champions League after losing badly against Manchester City. Bayern Munich's performance in the Bundesliga was not good either.
Tuchel in Munich is not yet successful. Out of 12 matches, Bayern Munich has won 6 matches and lost 4 matches. We are not sure if Tuchel can strengthen this team next season. But Tuchel is experienced enough. Hopefully, he will be successful with the Munich team.