Problems with unlocking levels

In the menu I put an option for the levels to be unlocked as I pass them. In this case, once passed, I can choose the level that I already passed. At the moment I have 10 levels. To give an example, it happens to me that when I choose to start from level 5 and go to level 6, the following are blocked. From 7 to 10 they are blocked and I have to unblock them again. How could I modify the code so that once it is unlocked it does not lock again? Here is the script i’m using:

 using System.Collections;
 using System.Collections.Generic;
 using UnityEngine;
 using UnityEngine.UI;
 using UnityEngine.SceneManagement;
  
 public class LevelSelector : MonoBehaviour
 {  
     public Button[] levelBTN;  
     public SceneLogic sceneLogic;
  
     void Start()
     {    
         //To unlock levels
         int level = PlayerPrefs.GetInt("level", 1);
  
         for (int i = 0; i < levelBTN.Length; i++)
         {
             if (i + 1 > level)
                 levelBTN*.interactable = false;* 

}
}

public void levelToLoad(int level)
{
SceneManager.LoadScene(level);

}

public void ButtonPressed1()
{
sceneLogic.IndiceDeNiveles = 0;
PlayerPrefs.SetInt(“CorrespondingLevel”, sceneLogic.LevelsIndex);
}
public void ButtonPressed2()
{
sceneLogic.IndiceDeNiveles = 1;
PlayerPrefs.SetInt(“CorrespondingLevel”, sceneLogic.LevelsIndex);
}
public void ButtonPressed3()
{
sceneLogic.IndiceDeNiveles = 2;
PlayerPrefs.SetInt(“CorrespondingLevel”, sceneLogic.LevelsIndex);
}
public void ButtonPressed4()
{
sceneLogic.IndiceDeNiveles = 3;
PlayerPrefs.SetInt(“CorrespondingLevel”, sceneLogic.LevelsIndex);
}
public void ButtonPressed5()
{
sceneLogic.IndiceDeNiveles = 4;
PlayerPrefs.SetInt(“CorrespondingLevel”, sceneLogic.LevelsIndex);
}
public void ButtonPressed6()
{
sceneLogic.IndiceDeNiveles = 5;
PlayerPrefs.SetInt(“CorrespondingLevel”, sceneLogic.LevelsIndex);
}
public void ButtonPressed7()
{
sceneLogic.IndiceDeNiveles = 6;
PlayerPrefs.SetInt(“CorrespondingLevel”, sceneLogic.LevelsIndex);
}
public void ButtonPressed8()
{
sceneLogic.IndiceDeNiveles = 7;
PlayerPrefs.SetInt(“CorrespondingLevel”, sceneLogic.LevelsIndex);
}
public void ButtonPressed9()
{
sceneLogic.IndiceDeNiveles = 8;
PlayerPrefs.SetInt(“CorrespondingLevel”, sceneLogic.LevelsIndex);
}
public void ButtonPressed10()
{
sceneLogic.IndiceDeNiveles = 9;
PlayerPrefs.SetInt(“CorrespondingLevel”, sceneLogic.LevelsIndex);
}
}
I should create a function that if it is 10 levels and I choose level 5, it should check if levels 6 to 10 are locked or unlocked. If they are unlocked, I should leave them unlocked if I go to 6. And if they are locked, I should leave them locked. Any idea how to do that?

You are setting the Playerprefs int but not getting it again.

Code something like:

if(PlayerPrefs.GetInt("CorrespondingLevel") == *wanted level*)
{
//unlock code
}