How to make an object smaller when it is hovering over another?

So my idea is I got a card and a delete button and I wanted to make the card diminish in size if its hovering over the delete button and once its dropped the card gets deleted.

From what I searched I need to use OnCollisionEnter2D but I still haven't found a way

This is the script I'm using to drag the card and I tried just doing the if its hovering gets deleted instantly part to test but its not working. I have defined the OnCollisionEnter2D function but I don't know how to call it inside the void Update().

using System.Collections;
using System.Collections.Generic;
using UnityEngine;

public class DragDrop : MonoBehaviour
{
    private bool isDragging;
    private int hovering = 0;
    private Vector3 startPos;
    private void OnCollisionEnter2D(Collider hit)
    {
        if (hit.transform.gameObject.name == "deleteButton")
        {
            Destroy(this);
        }
    }
    private void Start()
    {
        startPos = transform.position;
    }

    public void OnMouseDown()
    {
        isDragging = true;
    }

    public void OnMouseUp()
    {
        isDragging = false;
    }

    void Update()
    {
        if (isDragging)
        {
            Vector2 mousePosition = Camera.main.ScreenToWorldPoint(Input.mousePosition) - transform.position;
            transform.Translate(mousePosition);


        }  
        else
        {
            transform.position = startPos;
        }
    }
}

Also both my objects already have hitbox's.