Indeed. No manager will stay forever, someday he must leave the team. When a new coach/manager comes, he must have some challenges. He needs to adapt with the players and the atmosphere of the competition. Sometimes it takes for more than 1 season to adapt well and manage the team in the right way. Choosing the right strategy/tactics must know the players first, it won't be easy and won't be in a short time. Even a coach is an experienced person, it won't be an instant process to adapt with a new team.
today as today it is like this, a coach who wins everything with a team later feels the need to find new challenges and win things that he has not won
the era of coaches who stay decades no longer exists, precisely for this reason
now at certain levels, money is relative, they want titles