How do I disable left mouse rotation from PlayerCameraManager?

Having spring-arm is entirely upto you.

Can you explain what happens when you try to rotate? Please remeber that with my implementation, you must hold the right-mouse button and then drag to rotate.

Also you need two axis bindings defined in the Project settings.

These are

  1. MouseDragX (bound to MouseX)
  2. MouseDragY (bound to MouseY)

If it is still not working, let me see your blueprint and Input bindings.

PS: Also remember to turn off ** ‘Use Controller rotation’ ** option in Camera properties.