Every team has its glory days and like Bayern Munich is currently in decline because of the mistakes it made in the past, and what you said is true that the first mistake made by Bayern Munich management was when they fired Nagelsmann.
A tough task awaits Kompany because the Bundesliga is currently very competitive with the rise of several teams, especially Leverkusen, which is making it increasingly difficult for Bayern Muncih to dominate the Bundesliga like it did in the past.
To be honest, I have a little doubt about Kompany because he doesn't have experience, especially now that Bayern is in a slump, of course it will be a little difficult to get this team back up.
Bayern Munich this season has experienced a bad phase since their journey in the Bundesliga, Bayern Munich slump certainly surprised us all because previously Bayern Munich was in good condition without any signs of their slump, but after Nagelsman dismissal was carried out, Munich suddenly seemed to lose direction and also ambition in winning even though it was in the hands of a coach as great as Tuchel, Bayern Munich have squad of great players but failed to show their positive performance in the Bundesliga and even when hopes began to arise if Bayern Munich could compete in the Champions League, but they also had to suffer a defeat to Madrid.
Kompany, who this season officially became the coach of a big team, will certainly have a tough challenge to return to the performance of Bayern Munich next season, so far Bayern Munich is of course the first big team he has coached, although indeed Kompany have limited experience in European competitions, but he is known for his aggressive character and style of play so far, I think Kompany has shown high spirit and motivation and of course the courage to take on the challenge to be willing to coach a team as big as Bayern Munich.