<Servant leadership works really well when you have high agency individuals, and can grow high agency individuals. I have definitely been on the other side of that with control freak Machiavellian / nearly adversarial leaders as well.>

This. Every time I've lead people, IF they were already or were able to become high agency, we were efficient and capable. Control freak managers were usually guilty of what they obsessed over before they became managers. Good workers always leave bad managers in time, which always hurts the company.