Score System help

Hey Unity community so i tried a new high score system for my game but im running into a few problems with it which i need help on.

Issue #1 : The score is displayed, but the “Best Score” is always 0 is there anyway to make best score show the previous highest score in the game? Pic

Issue #2 : I Have it where the score system isn’t displayed at the very beginning, but it does not turn back on after the game is over. Is there anyway to show the score display after the game ends? In the Pic i provided i had to manually turn it on in the hierarchy/Inspector view. I want it to turn on after the player has lost all their lives.

Here is my scripts

void OnGUI()
{

  if (playerLives == 0 && player == null) 
	
		{

		scoreTxt.text = "Score: " + score.ToString ();
		bestText.text = "Best: " + PlayerPrefs.GetInt ("Best");
		
		scoreTxt.gameObject.SetActive (true);
		bestText.gameObject.SetActive (true);
		
		}
  }

If you can help with my issue thank you!

You need to compare both scores using Mathf.Max

This will return the highest score between to variables.