Scrolling ground

Hello guys, help needed So I am developing a little endless runner and have problem with spawning the tiles. Problem is that I decided to make player static, so instead of player movement-tiles move themselves and illusion of movement is created . It's pretty good move for optimization btw. Spawning starts after player is grounded(player is flying down a bit after start) and spawning occurs according first tile rotation and position. Relevant code snippets are included. These methods work if player has locomotion, not vice versa.

  public GameObject[] prefabs;
     public float zSpawn = 0f;
     public float tileLength = 30f;
     public int numberOfTiles = 3;
     public float xmultiplier = -3.1f;
     public float xadditive = 3.1f;
  
 private List<GameObject> activeTiles = new List<GameObject>();
 void Update()
     {
         //change logic here
         if (player.transform.position.z - 35 > zSpawn - (numberOfTiles * tileLength))
         {
             SpawnTile(gameStartScript.GetFirstTile().transform, Random.Range(0, prefabs.Length));
             DeleteTile();
         }
     }
 private void LateUpdate()
     {
         if (gameStartScript.gameStarted && playerController.isAirborn == false)
         {
             foreach (var tile in activeTiles)
             {
                 tile.transform.Translate(tile.transform.forward * playerController.speed * Time.deltaTime);
             }
         }
     }
     public void SpawnTile(Transform firstTile, int tileIndex)
     {
         //change logic here
         GameObject tileGameObject = Instantiate(prefabs[tileIndex]);
         tileGameObject.transform.position = firstTile.position;
         tileGameObject.transform.rotation = firstTile.rotation;
         tileGameObject.transform.position = new Vector3(tileGameObject.transform.position.x + xmultiplier, tileGameObject.transform.position.y, firstTile.position.z + zSpawn);
         activeTiles.Add(tileGameObject);
         zSpawn += tileLength;
         xmultiplier += xadditive;
     }
 void DeleteTile()
     {
         Destroy(activeTiles[0]);
         activeTiles.RemoveAt(0);
     }