I want to make text appear for a few seconds and then disappear.

The text is when player don't have the item. It's like "you don't have this item...". It's on line 39 & 40. Basically i want to make it from true to false for noKeyUI and false to true for interactUI. This is my code:

 using System.Collections;
 using System.Collections.Generic;
 using UnityEngine;
 using UnityEngine.UI;
 
 public class PlayerInteraction : MonoBehaviour
 {
     [SerializeField] private Text interactUI;
     [SerializeField] private Text noKeyUI;
     public GameObject currentObj = null;
     public ObjectInteraction currentObjScript = null;
     public Inventory inventory;
     
     void Update()
     {
         if (Input.GetKeyDown(KeyCode.E) && currentObj)
         {
             if (currentObjScript.inventory)
             {
                 inventory.AddItem(currentObj);
             }
 
             //check if the door can be opened
             if (currentObjScript.canOpen)
             {
                 //check if the door is locked
                 if (currentObjScript.locked)
                 {
                     //check if player have the key - unlock if have the key
                     if (inventory.FindItem(currentObjScript.itemNeed))
                     {
                         currentObjScript.locked = false;                       
                     }
 
                     else
                     {
                         noKeyUI.gameObject.SetActive(true);
                         interactUI.gameObject.SetActive(false);
                     }
                 }
 
                 else
                 {
                     currentObjScript.SwitchLevel();
                 }
             }
         }
     }
 
     void OnTriggerEnter2D(Collider2D other)
     {
         if (other.CompareTag("InterObj"))
         {
             interactUI.gameObject.SetActive(true);
             currentObj = other.gameObject;
             currentObjScript = currentObj.GetComponent<ObjectInteraction>();
         }
     }
 
     void OnTriggerExit2D(Collider2D other)
     {
         interactUI.gameObject.SetActive(false);
 
         if (other.CompareTag("InterObj"))
         {
             if (other.gameObject == currentObj)
             {
                 currentObj = null;
             }
         }
     }
 }