question about optimization script damage

Hello! I created damage to the script , but I doubt very much in its " ease " for performance ... what advise ? its essence : when hit by a physical object , a sphere - Collider appears and puts all the enemies in the array , and each gets a unique damage , depending on the distance from the explosion.

 using UnityEngine;
 using System.Collections;
 using System.Collections.Generic;
 
 public class SplashAttack : MonoBehaviour {
 
     public float radius = 10f, multiply = 1.0f, damage = 5.0f, aa = 0.1f;
     public List<damageSizeData> damageSize;
     Collider[] hitUnits;
 
     void OnCollisionEnter(Collision collision)
     {
         StartCoroutine(ExplosionDamage());
     }
 
     IEnumerator ExplosionDamage()
     {
       hitUnits = Physics.OverlapSphere(transform.position, radius);
       for (int i = 0; i < hitUnits.Length; i++)
           if (hitUnits[i].tag == "Enemy" || hitUnits[i].tag == "Player")
             {
                 foreach (damageSizeData dist in damageSize)
                     if (Vector3.Distance(hitUnits[i].transform.position, transform.position) >= dist.distance)
                         damage = dist.damage;
                 hitUnits[i].gameObject.GetComponent<Warior>().GetMySquard().AttacktoMe(damage, aa, multiply);
             }
         Destroy(gameObject);
         yield break;
     }
 
     [System.Serializable]
     public struct damageSizeData
     {
         public float distance;
         public float damage;
     }
 }