Need Distance-Based Score Multiplier For Multiple Assets (Typing Rhythm Game)

So, I'm a college student majoring in game design that's been messing around in Unity for the past few days and while I have a good amount of standard Java experience, I'm stranded in C# and how exactly to access certain things, etc. etc. What I'm trying to make is a rhythm typing game, where as the letters get closer to an on-screen keyboard your point total increases as a song plays in the background. After hours of work, I was able to get a distanceMultiplier to work, but I can't access it. I've tried many things. I've searched the forums, scanned Google, and every answer is either more complicated than I can understand or does not solve my particular issue. I've attached the code for the two scripts that apply here: my GameManager, and my DistanceMeasure. I have a DistanceMeasure script applied to every letter PreFab that falls down on the screen, and the only work-around I've found to at least get the GameManager to recognize the DistanceMultiplier only allows me to measure a single letter's distance. Sorry if any of my explanation is confusing, I've been troubleshooting this logic error for 4 hours now and have finally given up, so any help is appreciated at this point. Thanks for reading!

 public class GameManager : MonoBehaviour
 {
 
     public AudioSource music;
 
     public bool startPlaying;
 
     public BeatScroller theBS;
 
     public DistanceMeasure theDM;
 
     public static GameManager instance;
 
     public int currentScore;
     public int scorePerNote;
 
     public Text scoreText;
 
     public int currentMultiply;
     public int streak;
     public int[] multiplier;
 
 
     // Start is called before the first frame update
     void Start()
     {
         instance = this;
         scoreText.text = "0";
         currentMultiply = 1;
         streak = 0;
 
     }
 
     // Update is called once per frame
     void Update()
     {
 
         if (!startPlaying)
         {
             if (Input.anyKeyDown)
             {
                 startPlaying = true;
                 theBS.hasStarted = true;
 
                 music.Play();
             }
         }
 
     }
 
     public void NoteHit()
     {
         int distanceMultiply = theDM.distanceMultiplier;
 
         Debug.Log("Hit");
 
         if (currentMultiply - 1 < multiplier.Length)
         {
            
             streak++;
 
             if (multiplier[currentMultiply - 1] <= streak)
             {
                 streak = 0;
                 currentMultiply++;
             }
 
         }
 
         currentScore += scorePerNote * currentMultiply * distanceMultiply;
         
         scoreText.text = currentScore.ToString();
 
     }
 
     public void NoteMiss()
     {
         Debug.Log("Missed");
 
         streak = 0;
         currentMultiply = 1;
 
     }
 }
 
 public class DistanceMeasure : MonoBehaviour
 {
     public GameObject key;
     public GameObject letter;
 
     public float distanceBetween;
     public int distanceMultiplier;
 
     // Start is called before the first frame update
     void Start()
     {
         
     }
 
     // Update is called once per frame
     void Update()
     {
         distanceBetween = Vector3.Distance(key.transform.position, letter.transform.position);
         distanceBetween = Mathf.Abs(Mathf.Ceil(distanceBetween));
 
         switch (distanceBetween)
         {
             case 20:
                 distanceMultiplier = 1;
                 break;
             case 19:
                 distanceMultiplier = 2;
                 break;
             case 18:
                 distanceMultiplier = 3;
                 break;
             case 17:
                 distanceMultiplier = 4;
                 break;
             case 16:
                 distanceMultiplier = 5;
                 break;
             case 15:
                 distanceMultiplier = 6;
                 break;
             case 14:
                 distanceMultiplier = 7;
                 break;
             case 13:
                 distanceMultiplier = 8;
                 break;
             case 12:
                 distanceMultiplier = 9;
                 break;
             case 11:
                 distanceMultiplier = 10;
                 break;
             case 10:
                 distanceMultiplier = 11;
                 break;
             case 9:
                 distanceMultiplier = 12;
                 break;
             case 8:
                 distanceMultiplier = 13;
                 break;
             case 7:
                 distanceMultiplier = 14;
                 break;
             case 6:
                 distanceMultiplier = 15;
                 break;
             case 5:
                 distanceMultiplier = 16;
                 break;
             case 4:
                 distanceMultiplier = 17;
                 break;
             case 3:
                 distanceMultiplier = 18;
                 break;
             case 2:
                 distanceMultiplier = 19;
                 break;
             case 1:
                 distanceMultiplier = 20;
                 break;
             case 0:
                 distanceMultiplier = 25;
                 break;
             default:
                 distanceMultiplier = 1;
                 break;
 
         }
     }
 }