Why does the object not move on the Z-Axis?

I asked this on the Forum, but this is a better place to ask. This is a placement script for moving objects for a grid-based placing game that is focused on earning money. It's working perfectly fine, except for the fact that it only moves on the X-axis and not the Z-axis. Does anyone have a solution?

 using System.Collections;
 using System.Collections.Generic;
 using UnityEngine;
  
 public class PlaceableBuilding : MonoBehaviour
 {
     private Transform currentBuilding;
     private bool hasPlaced;
     private BuildingManager bm;
     public Transform grid;
     public List<GameObject> border = new List<GameObject>();
  
     public float minX, maxX, minZ, maxZ;
  
     private void Start()
     {
         bm = GetComponent<BuildingManager>();
     }
  
     private void Update()
     {
         if(currentBuilding != null && !hasPlaced)
         {
             Vector3 mouse = Input.mousePosition;
             mouse = new Vector3(mouse.x, mouse.y, transform.position.y);
             Vector3 pos = Camera.main.ScreenToWorldPoint(mouse);
             currentBuilding.position = new Vector3(pos.x, 0, 2);
  
             if(Input.GetMouseButton(0))
             {
                 Vector3 p = new Vector3(currentBuilding.localPosition.x, currentBuilding.localPosition.y, currentBuilding.localPosition.z);
  
                 float nx = Mathf.Round(Camera.main.ScreenToWorldPoint(mouse).x);
                 float ny = Mathf.Round(Camera.main.ScreenToWorldPoint(mouse).y);
                 float nz = Mathf.Round(Camera.main.ScreenToWorldPoint(mouse).z);
  
                 Vector3 v = new Vector3 (nx, ny, nz);
                 if (nx > maxX || nx < minX || nz > maxZ || nz < minZ)
                 {
                     Debug.LogError("Out of Bounds");
                     Debug.Log(Camera.main.ScreenToWorldPoint(mouse));
                 } else if (nx <= maxX || nx >= minX || nz <= maxZ || nz >= minZ)
                 {
                     hasPlaced = true;
                 }
             }
         }
     }
  
     public void SetItem(GameObject item)
     {
         hasPlaced = false;
         currentBuilding = Instantiate(item, new Vector3(0, 0, 0), Quaternion.identity).transform;
     }
 }