Knockback.cs

using System.Collections;
using System.Collections.Generic;
using UnityEngine;
using DG.Tweening;
public class KnockBack : MonoBehaviour
{

    public Rigidbody2D theRB;
    public float thrust;
    public float knockTime;
    public string otherTag;
    private void OnTriggerEnter2D(Collider2D other)
    {
        if(other.gameObject.CompareTag("Enemy") && other.isTrigger)
        {
            Rigidbody2D hit = other.GetComponentInParent<Rigidbody2D>();
            if (hit != null)
            {

                // hit.AddForce(difference, ForceMode2D.Impulse);

                if (other.gameObject.CompareTag(otherTag) && other.isTrigger)
                {
                    hit.GetComponent<EnemyController>().currentState = EnemyStates.stagger;
                    other.GetComponent<EnemyController>().Knock(hit, knockTime);
                }

                if (other.GetComponent<PlayerController>().state != PlayerState.stagger)
                {
                    hit.GetComponent<PlayerController>().state = PlayerState.stagger;
                    Knock(knockTime);
                }

            }
        }
    }

    public void Knock(float knocktime)
    {
        StartCoroutine(Knockco(knocktime));
    }

    private IEnumerator Knockco(float knockTime)
    {
        if (theRB != null)
        {
            yield return new WaitForSeconds(knockTime);
            theRB.velocity = Vector2.zero;
            theRB.velocity = Vector2.zero;
        }
    }
}