To make a rotating camera that spins around a central point, make a new Blueprint of type Actor. Inside the blueprint add two components, a billboard – so you can visualise the center, and a camera. Drag the camera away from the centre in X direction, and add another component, Rotating Movement. Pressing simulate will show the camera moving in a circle pointing at the centre. The rotation speed can be altered.
This blueprint can be dragged into the level and moved around to get the right centre and motion. Use this tip here to set this camera to be the default.