HI I'm having a problem with spawning objects

I've been playing around with some YouTube videos for object spawning, but I'm having a bit of an issue. When I run the game, the whole screen gets crowded with the objects, and I have no idea why its happening. Can anyone tell me why this is occurring? Below is the code that i'm using, i have also posted an image of the outcome.

Thanks

    [SerializeField]
     private float xLimit;
     [SerializeField]
     private float[] xPositions;
     [SerializeField]
     private GameObject[] emojiPrefabs;
     [SerializeField]
     private Wave[] wave;
 
 
     private float currentTime;
     List<float> remainingPositions = new List<float>();
     private int waveIndex;
     float xPos = 0;
     int rand;
     
     void Start()
     {
         currentTime = 0;
         remainingPositions.AddRange(xPositions);
     }
 
     void Update()
     {
         SelectWave(); 
     }
     void SpawnEnemy(float xPos) 
     {
         int r = Random.Range(0, 2); 
         Instantiate(emojiPrefabs[r], new Vector3(xPos, transform.position.y, 0), Quaternion.identity);
     }
     void SelectWave() 
     {
         remainingPositions = new List<float>();
         remainingPositions.AddRange(xPositions);
 
         waveIndex = Random.Range(0, wave.Length);
         currentTime = wave[waveIndex].delayTime;
 
         if(wave[waveIndex].spawnAmount == 1) 
         {
             xPos = Random.Range(-xLimit, xLimit);
         } else if(wave[waveIndex].spawnAmount > 1) 
         {
             rand = Random.Range(0, remainingPositions.Count);
             xPos = remainingPositions[rand];
             remainingPositions.RemoveAt(rand);
         }
 
         for (int i = 0; i < wave[waveIndex].spawnAmount-1; i++)
         {
             SpawnEnemy(xPos);
             rand = Random.Range(0, remainingPositions.Count);
             xPos = remainingPositions[rand];
             remainingPositions.RemoveAt(rand);
         }
     }
 }
 [System.Serializable]
 public class Wave 
 {
     public float delayTime;
     public float spawnAmount;
 }