How do I deal with managing a planning department instead of designing?

You trained to shape places, to draw the plan that makes a neighborhood work. Now it is staff and hearings and politics, and the drawing board belongs to someone else. That is a real loss to sit with. The design was where you felt you mattered. But the hearings and the fights are where good design lives or dies. You protect the vision from the forces that would flatten it. Every plan your team gets built well passes through the shield you hold. That is planning at a larger scale. Keep a hand in one design. Sketch, review, sit with your team over a plan. It reminds you what the meetings are for and keeps your eye sharp for the work worth fighting to build.