3D场景中2D Sprite显示问题：敌人正对玩家前停止旋转问询

我在3D环境中使用2D Sprite时遇到一个问题：当Sprite与摄像机垂直时会无法显示。我已经通过跟踪鼠标位置解决了玩家角色的该问题，代码如下：

if (lookAtMouseEnabled)
{
    Lookatmouse();
}
Vector3 mousePos = Input.mousePosition;
//Debug.Log($"Mouse X: {mousePos.x}");

if (mousePos.x >= minXRotation && mousePos.x <= maxXRotation)
{
    lookAtMouseEnabled = false;
}
else
{
    lookAtMouseEnabled = true;
}

但敌人角色无法采用同样的方法，我需要实现：判断玩家在敌人的左侧还是右侧，让敌人在正对玩家前20度时停止旋转，反向情况也一样。敌人当前的代码如下：

public Transform player;
public float speed = 5.0f;
public float rotationSpeed = 10.0f;
public float chaseDistance = 2.0f;
public float stoppingDistance = 1.0f;

private Rigidbody rb;

void Start()
{
    rb = GetComponent<Rigidbody>();
}

void FixedUpdate()
{
    if (player == null)
    {
        GameObject playerObject = GameObject.FindGameObjectWithTag("Player");
        if (playerObject != null)
        {
            player = playerObject.transform;
        }
    }

    if (player != null)
    {
        Vector3 direction = player.position - transform.position;
        float distance = direction.magnitude;

        if (distance > stoppingDistance)
        {
            //Rotation
            direction.Normalize();
            Quaternion lookRotation = Quaternion.LookRotation(direction);
            rb.rotation = Quaternion.Slerp(rb.rotation, lookRotation, rotationSpeed * Time.fixedDeltaTime);

            //ChasePlayer
            Vector3 chasePosition = player.position - player.forward * chaseDistance;
            Vector3 newPosition = Vector3.MoveTowards(rb.position, chasePosition, speed * Time.fixedDeltaTime);
            rb.MovePosition(newPosition);

            // Determine if the player is on the left or right
            Vector3 enemyToPlayer = player.position - transform.position;
            Vector3 enemyRight = transform.right; 
            float dotProduct = Vector3.Dot(enemyToPlayer, enemyRight);

            if (dotProduct < 0)
            {
                Debug.Log("Player is on the left.");
            }
            else
            {
                Debug.Log("Player is on the right.");
            }
        }
    }
}

问题截图：

现寻求该问题的解决方案，恳请各位提供建议。

内容的提问来源于stack exchange，提问作者Spectral Visions