I agree with you that it is like Bayern Munich is starting all over again since a new coach was brought to take over from Tuchel. If it was Tuchel, I will say that by now he has understood the players and their capabilities on how to use and mange them to bring good results for the club, because I will say that he was learning last season.
Kompany is on a new club which he is meeting these players for the first time to coach them and he will need time to learn about these players and their strengths to know how he can fit them into his game tactics, which will not be something easy. This is why I still think that next season will not be a victorious season for Bayern Munich because the other clubs are also ready to win the league.
Bundesliga title was won by Bayer Leverkusen because Bayern Munich wad not in form previous season. The Bavarians are here to stationed winning and we know it's up and running. Bayern Munich new coach will do better, I know this actual fact for sure. Vincent Kompany is classified mediocre because Bayern Munich happens to be the first top flight club to manage as coach and we know what's capable of, he will put in enough work for the purpose to succeed in his first season.
When I saw what Xabi did in his first season at Leverkusen, my attitude towards coaches has changed. Experience is of course important, but each coach must be given sufficient time. Kompany is perhaps a coach who can teach Bayern important football tactics. I'm sure their main goal will be to leave Leverkusen behind.