Can You help me Fix This? (Infinite level Generator)

I am making a game called Boxel Run 3D, and I am in process of making an infinite level gen. This is THE LAST THING I need to code to finish the game, but I could not fix it FOR 6 MONTHS. It kind of works, but when you are about to move from one tile to another, the tile disappears underneath your feet, and you die.

Here is my code:

using System.Collections; using System.Collections.Generic; using System.Net.NetworkInformation; using UnityEditor; using UnityEngine; using UnityEngine.PlayerLoop;

public class LevelController : MonoBehaviour { public LevelPiece[] levelPieces; public int DrawDistance; public float pieceLength; public Transform _camera; float currentcamStep; float lastcamStep; public float ttw = 1.0f; public float done = 0.0f; public float speed;

 Queue<GameObject> activePieces = new Queue<GameObject>();
 List<int> probabilityList = new List<int>();
 private void Start() {
     BuildProbabilityList();
     for (int i = 0; i < DrawDistance; i++) {

           SpawnNewPieces();

     }
     currentcamStep = (int)((_camera.transform.position.z + 3.15) / pieceLength);
     lastcamStep = currentcamStep;
 }
 private void Update() {
     _camera.transform.position = Vector3.MoveTowards(_camera.transform.position, _camera.transform.position + Vector3.forward, Time.deltaTime * speed);
     currentcamStep = (int)(_camera.transform.position.z / pieceLength);
     if (currentcamStep != lastcamStep) {
         
         DespawnPiece();
         lastcamStep = currentcamStep;
         SpawnNewPieces();
         
     }
 }
 void SpawnNewPieces() {
     int pieceIndex = probabilityList[UnityEngine.Random.Range(0, probabilityList.Count)];
     GameObject newLevelPiece = Instantiate(levelPieces[pieceIndex].prefab, new Vector3(0f, 0f, pieceLength * (currentcamStep + activePieces.Count) * pieceLength), Quaternion.identity);
     activePieces.Enqueue(newLevelPiece);
 }
 void DespawnPiece() {

     //wait for seconds?
     GameObject oldLevelPiece = activePieces.Dequeue();
     Destroy(oldLevelPiece);

 }

 void BuildProbabilityList() {

     int index = 0;
     foreach (LevelPiece piece in levelPieces) {

         for (int i = 0; i< piece.probability; i++) {

             probabilityList.Add(index);

         }
         index++;
     }

 }

} [System.Serializable] public class LevelPiece { public string name; public GameObject prefab; public int probability = 1; }

Any Ideas? (Btw if you see random code it id for other things in my game :) )