Some good thoughts about team leadership.

The Scrum Guide seems confused about leadership - it keeps changing its mind: https://www.linkedin.com/pulse/scrum-very-confused-leadership-cliff-berg/

Leadership is a complex subject. It is also important to note that one of the dimensions of management is leadership. A PO usually is a manager of a business function, but you are right that they should not act as a manager of a development team.

The Agile 2 project attempted to define a leadership taxonomy, only because we could not find one that we felt was comprehensive. It is here: https://agile2.net/more-resources/a-leadership-taxonomy/

Please see the Agile 2 discussion of leadership here, under the section "Leadership" (the last and largest category): https://agile2.net/agile-2/the-values-and-principles-of-agile-2/

It is also worth pointing out that servant leadership is often misunderstood. Greenleaf himself said that when acting act as a servant leader, others _follow_ - his words. What makes a servant leader is that they develop the trust of the team; to do that, they must show that they have the team's interests at heart, and they must also demonstrate competence.