I can't kill more copies of the same enemy?

Hi guys, in short I can’t kill the copies of the same enemy. Even when I create the prefab of an enemy, and duplicated couple times, if I kill the other copies (not the first one I place on scene) I can only kill the first one I placed. can you take a look at my code attacking and give me some advice please.

Player feet script

public class PlayerAttack : MonoBehaviour {

public static PlayerAttack instance;

public int damageToGive;

private void Awake() {
    instance = this;
}

// Start is called before the first frame update
void Start() {
   
}

// Update is called once per frame
void Update() {
    
}

private void OnTriggerEnter2D(Collider2D other) {
    if (other.tag == "EnemyDamagableArea") {

        Debug.Log(gameObject + " has collided with " +
            other.gameObject + 
            "!!");
        //here I pass the damage that feet obj has to the enemy that was collided
        EnemyHealthManager.instance.giveDamage(damageToGive);

        PlayerController.instance.BounceJump();
    }
}

}

Enemy

Enemy class script
public class EnemyHealthManager : MonoBehaviour {

public static EnemyHealthManager instance;

[Header("Enemy Stats")]
public int enemyHP;

[Header("Death Explosion FX")]
public GameObject objExplosion;

private void Awake() {
    instance = this;
}

// Update is called once per frame
void Update() { 
    Die();
}

public void Die() {
    if (enemyHP <= 0) {

        Destroy(gameObject);

        Debug.Log("Enemy Dead!!!!" + " HP: " + enemyHP);

        GameObject explosion = (GameObject)Instantiate(objExplosion);
        explosion.transform.position = transform.position;
        Destroy(explosion, 0.80f);
    }
}
public void giveDamage(int damageToReceived) {
    enemyHP -= damageToReceived;

}

You are using a static instance of the EnemyHealthManager class, meaning there is only one instance of this class that you are interacting with. Instead, you need a separate instance attached to each enemy, and you need to use that enemy’s specific instance to apply damage using something like other.gameObject.GetComponent<EnemyHealthManager>().giveDamage(damageToGive)

any hints? I was thinking maybe this line “EnemyHealthManager.instance.giveDamage(damageToGive);” calling the class is updating only all the game objects of same type that is why I can kill the first enemy and the rest cannot be killed?