Is it permissible to abandon a manager who plots schemes and corrupts religious and worldly affairs, especially since he issued a circular prohibiting the mention of ideological thoughts inside the classroom and accused teachers of teaching jihad and niqab?

If the reason for abandonment (boycotting/shunning) is legitimate and entails a preponderant benefit that leads to the weakening of evil, then it is permissible. However, if the abandonment is based on personal whims and desires, then it is not permissible. Hearts should be reconciled and forgiveness extended for their safety from malice and resentment.