Firing rays in a cone shape from the player

Although some of my code seems to work, I am getting some unexpected results.

I have a for loop in which I create a new ray each time in a specific direction - which is where the problem lies. I want to trace a cone shape from the player in its forward direction. However, while the rays are cast in a circle or cone shape, the width or angle of this cone changes as the object moves rather than being set to a specific angle.

If I want to trace a cone shape with an angle of 30d from the center, it traces a cone shape centered around 30d, on the x axis in my case, instead. The angle changes as it moves.

How can I make it trace the cone shape specified by my angle around the forward direction?

         //search in circle around center
         float stepAngleDeg = 360 / subdivisions; //angle between two sampled rays
         for (int i = 0; i < subdivisions; i++)
         {
             Vector3 localRotation = new Vector3(angleFromCenter, 0, i * stepAngleDeg); //direction of Ray to cast in Euler XYZ form
             Vector3 direction = (Quaternion.Euler(localRotation) * transform.up).normalized; //turn rotation into direction
             
             Ray ray = new Ray (bulletSpawnPoint.position, direction);
             Debug.DrawLine(ray.origin, ray.origin + (direction * asteroidAvoidDistance), Color.red);
         }