Unable to get this score working C#

Unity Engine
1

My scoring system is not working as planned, and here is what is what is suppose to happen, and what is happening.

  1. Score should not populate when player hits an obstacle, but it still hits trigger and populates score when player hits an obstacle and does not correctly avoid the obstacle.

  2. Score should only multiply when player correctly avoids 3 obstacles, but it is multiplying every time we score.

Here is what i have so far, any help would be greatly appreciated.

public class Score_System : MonoBehaviour {
   
    public static int playerScore = 0;
    public int pScore = 10;
    private GameObject scoreText;
    public int combo = 0;
   
    void Start () {
        scoreText = GameObject.Find("scoreNumber");
    }
   
    void Update()
    {
        if (combo >= 3)
        {
            pScore = 20; //the increased points
        } else {
            pScore = 10;
        }
    }
   
    void OnTriggerEnter(Collider other)
    {
        if (gameObject.CompareTag ("Pickup")) {
            gameObject.SetActive (false);
            combo += 2;
            playerScore += pScore * combo;
            Debug.Log ("Points triggered");
        }
       
        if (gameObject.CompareTag ("obstacle"))
            combo = 0; //Resets the combo, but upon next pickup will gain +1 from the Pickup collider
        Debug.Log ("Combo reset");
               
   
        }
void OnGUI()
{
    scoreText.guiText.text = playerScore.ToString();
} 
}
2

You are comparing the tag of the game object the score system script is attached to, not of the collider you are hitting. Use other.gameObject.CompareTag() instead. Also, as a side note, the “combo reset” debug isn’t inside the if statement.

Furthermore, setting the score in the update loop does not make a whole lot of sense. There is no point in setting the score each frame; you should just do it when there has been an actual change.