Hop from transform to transform in 2D game?

Hi there, I have an array of transforms scattered around my scene, and I want my player to be able to move by jumping from one to the next (next meaning closest), in whichever direction they input. In the following function, I was able to get my guy to go from closest point to closest point, but I can't seem to figure out how to incorporate direction into it:

 Vector3 FindClosestPoint(Vector2 movementDirection)
     {
         Vector3 currentPosition = transform.position;
         Transform closestPoint = null;
         float distanceToClosestPoint = Mathf.Infinity;
 
         for (int i = 0; i < points.Length; i++)
         {
             Vector3 pointDirection = points[i].position - currentPosition;
             float pointAngle = Vector2.Angle(pointDirection, movementDirection);
             float distanceToPoint = Vector2.Distance(points[i].position, currentPosition);
 
             if (distanceToPoint < distanceToClosestPoint)
             {
                 if (pointAngle < 90)   // this is where I think my biggest logic error is
                     closestPoint = points[i];
                 distanceToClosestPoint = distanceToPoint;
             }
         }
         return closestPoint.position;
     }

The Vector2 param passed in is either Vector2.up, down, left, or right. I get a null reference exception when my "if (pointAngle < 90)" doesn't find anything - that if statement doesn't behave like I expect it to, instead of checking whether the angle between the direction I pass in and the direction of the target point is within my player's hardcoded 90 degree "cone of vision," it seems to be doing something else. I can never really predict which transform the player will jump to.