Is there a better way to code this because this is causing a major amount of lag

I am new to coding so I found some YouTube videos and typed some code from there. The problem is that the code is spawning too many objects right next to each other and is causing a lot of lag due to an explosion effect I added whenever an enemy comes in contact with anything. Is there a way to reduce the lag? (Also, if someone could tell me why my target and explosion effect are not assigned, even though I assigned them on the enemy character, that would be so helpful)

this is my code

using UnityEngine;

[RequireComponent(typeof(Rigidbody2D))]

public class Homing : MonoBehaviour {

 public Transform target;

 private Rigidbody2D rb;

 public float speed = 4f;

 public float rotateSpeed = 200f;

 public GameObject explosionEffect;

 void Start()
 {
     rb = GetComponent<Rigidbody2D>();
 }


 void FixedUpdate()
 {
     if(target != null)
     {
         Vector2 direction = (Vector2)target.position - rb.position;

         direction.Normalize();

         float rotateAmount = Vector3.Cross(direction, transform.up).z;

         rb.angularVelocity = -rotateAmount * rotateSpeed;

         rb.velocity = transform.up * speed;
     }
     
 }

 void OnTriggerEnter2D()
 {
     Instantiate(explosionEffect, transform.position, transform.rotation);
     Destroy(gameObject);
 }

}