Destroy Multiple Objects with tag

Hi :)

I'm now trying to destroy multiples tagged object, however, it doesn't work. The code is below:

 public GameObject TargetObj;
 
 void Update()
 {
     var num_TargetObj = GameObject.FindGameObjectsWithTag("Target_Obj").Length;
 
     if (Input.GetKeyDown("d"))
     {
         for (int i = 0; i <= 2; i++)
         {
             GameObject.Destroy(GameObject.Find("Plane_Target(Clone)"));
         }
     }
 
     if (Input.GetKeyDown("g"))
     {
         GenerateObj();
     }
 }
 
 public void GenerateObj()
 {
     var num_TargetObj = GameObject.FindGameObjectsWithTag("Target_Obj").Length;
 
     if (num_TargetObj < 2)
     {
         Instantiate(TargetObj, new Vector3(2, 1, 1), Quaternion.identity);
         Debug.Log("Generate right");
         Instantiate(TargetObj, new Vector3(-2, 1, 1), Quaternion.identity);
         Debug.Log("Generate left");
     }
 }

I checked some past conversation, however, they described the object should destroy once when the script found the tagged object. If I execute this script, it seems the script delete only one object for every frame (so I need to call destroy function for two frames if I want to delete two generated objects.

I'm quite new for unity, so probably I might missed something. Any advice will help me, thank you very much in advance.