MissingReferenceException even after checking if object is null

I have been learning Unity for a couple of weeks, and I am working on a prototype for a game. I am trying to add death effects for the traps in the game (sounds and particles), but also have them rotate towards the Player. Since adding the particle effects, I get the MissingReferenceException error for all the traps in my scene. It sends me to Vector3 directionToTarget = target.transform.position - this.transform.position; I tried to verify if the object is not null, but I get the same result. The last two added voids are a desperate attempt to figure it out on my own. Can anyone help me figure out what I am doing wrong? Thank you in advance! This is my messy code:

 using System.Collections;
 using System.Collections.Generic;
 using UnityEngine;
 
 public class Trap : MonoBehaviour
 {
     public ParticleSystem deathSpark;
     //public GameObject deathSpark;
     [SerializeField] private Transform target;
 
     private enum FollowType { Forward, Up, Right }
 
     // This is seperate for each cube in the inspector, so I can configure them accordingly
     [SerializeField] private FollowType follow;
 
     private void Update()
     {
         // Get the direction to the target by subtracting the target position by the current position.
         if (gameObject != null)
         {
             Vector3 directionToTarget = target.transform.position - this.transform.position;
 
             switch (follow)
             {
                 case FollowType.Forward:
                     transform.forward = directionToTarget;
                     break;
                 case FollowType.Up:
                     transform.up = directionToTarget;
                     break;
                 case FollowType.Right:
                     transform.right = directionToTarget;
                     break;
                 default:
                     break;
             }
         }
     }
     private void OnTriggerEnter(Collider other)
     {
         if ((gameObject != null) && gameObject.CompareTag("BoHead"))
         {
             SoundManagerScript.PlaySound("Heavy Object Impact 4");
             Instantiate(deathSpark, transform.position, Quaternion.identity);
             CreateExplosion();
             //Instantiate(deathSpark, transform.position, transform.rotation);
             //Destroy(gameObject);
             
         }
     }
     void CreateExplosion()
     {
         if (gameObject != null)
         {
             Instantiate(deathSpark, transform.position, Quaternion.identity);
             deathSpark.Play();
         }
     }
 
     public void Destroy()
     {
         if (gameObject != null)
         {
             SoundManagerScript.PlaySound("Heavy Object Impact 4");
             Instantiate(deathSpark, transform.position, Quaternion.identity);
            
         }   
     }
 }