Issue with equipping object

When picking up an object, they are automatically added to the inventory. I can correctly add the item to my hand when I press "1". However, when I press "2" the second item stacks on top of the first item.

However, when I press "1" again, the second item disappears correctly and when I press "2" again, the first item disappears correctly.

The problem is that the first item will not disappear correctly when I press "2" for the first time. It only works correctly when I press "1" twice.

What exactly is the issue here? I've tried deactivating the object when another button is pressed, but I get the same result. Here's some of the code I am talking about.

Select Items to be Equipped

 void SelectItems()
     {
         foreach (GameObject item in items)
         {
             if (Input.GetKeyDown(KeyCode.Alpha1) && items.Count >= 1)
             {
                 items[itemToBeEquipped].GetComponent<ItemData>().UnequipItem();
                 itemToBeEquipped = 0;
                 items[itemToBeEquipped].GetComponent<ItemData>().EquipItem();
                 Debug.Log("Item 1 Equipped");
                 
             }
             else if (Input.GetKeyDown(KeyCode.Alpha2) && items.Count >= 2)
             {
                 items[itemToBeEquipped].GetComponent<ItemData>().UnequipItem();
                 itemToBeEquipped = 1;
                 items[itemToBeEquipped].GetComponent<ItemData>().EquipItem();
                 Debug.Log("Item 2 Equipped");
             }
             else if (Input.GetKeyDown(KeyCode.Alpha3) && items.Count >= 3)
             {
                 items[itemToBeEquipped].GetComponent<ItemData>().UnequipItem();
                 itemToBeEquipped = 2;
                 items[itemToBeEquipped].GetComponent<ItemData>().EquipItem();
                 Debug.Log("Item 3 Equipped");
             }
             else if (Input.GetKeyDown(KeyCode.Alpha4) && items.Count >= 4)
             {
                 items[itemToBeEquipped].GetComponent<ItemData>().UnequipItem();
                 itemToBeEquipped = 3;
                 items[itemToBeEquipped].GetComponent<ItemData>().EquipItem();
                 Debug.Log("Item 4 Equipped");
             }
             else if (Input.GetKeyDown(KeyCode.Alpha5) && items.Count == 5)
             {
                 items[itemToBeEquipped].GetComponent<ItemData>().UnequipItem();
                 itemToBeEquipped = 4;
                 items[itemToBeEquipped].GetComponent<ItemData>().EquipItem();
                 Debug.Log("Item 5 Equipped");
             }
         }
     }

PickUpItem Method

 public void PickUpItem()
     {
         if (InventoryScript.items.Count < 5)
         {
             //disable picked up item colliders and rigidbody
             coll1.enabled = false;
             coll2.enabled = false;
             rb.isKinematic = true;
 
             gameObject.transform.parent = pos_pickedUpItem.transform;
             gameObject.transform.position = pos_pickedUpItem.position;
             isInInventory = true;
             isEquipped = true;
             InventoryScript.itemToBeEquipped = InventoryScript.items.Count;
             InventoryScript.items.Add(gameObject);
             EquipItem();
             gameObject.GetComponent<MeshRenderer>().enabled = false;
 
             //Debug.Log("Picked up " + str_ItemName + "!");
             //Debug.Log("There are " + InventoryScript.items.Count + " in your inventory");
         }
         else if (InventoryScript.items.Count == 5)
         {
             Debug.Log("Error: Not enough space to pick up this item!");
         }
     }

Equip / Unequip Method

 public void EquipItem()
     {
         gameObject.GetComponent<MeshRenderer>().enabled = true;
         isEquipped = true;
         isActivated = true;
         //gameObject.SetActive(true);
 
         //Debug.Log("Equipped " + str_ItemName + "!");
     }
     public void UnequipItem()
     {
         gameObject.GetComponent<MeshRenderer>().enabled = false;
         isEquipped = false;
         isActivated = false;
         //gameObject.SetActive(false);
 
         //Debug.Log("Unequipped " + str_ItemName + "!");
     }