How to increase speed using the coroutine?

Right now im making a ping pong game. After programming a simple ball movement, I need to create speed increasing so it doesn’t get boring. The main twist is that I must use a coroutine. I don’t have any ideas on how to write my code. Can someone help me
I have this so far :
[P.S speed increasing might be written in another class]

using System.Collections;
using Random = UnityEngine.Random;
using System.Collections.Generic;
using UnityEngine;
using System;
using Unity.VisualScripting;

public class BallController : MonoBehaviour
{
    public float BaseSpeed;
    public float MaxSpeed;
    public float Acceleration;
    public float SpawnMovementDelay;

    [SerializeField]private Rigidbody2D _ball;

    private Rigidbody2D _ballInstance;
    private BallMovementHandler _movementHandler;

    private void Start()
    {
        _movementHandler = GetComponent<BallMovementHandler>();
    }

    private void Update()
    {
        if (Input.GetKeyDown(KeyCode.LeftControl))
        {
            Instantiation();
            StartCoroutine(Delay());
            StartCoroutine(_movementHandler.SpeedIncreasing());
        }
    }
    public void Instantiation()
    {
        _ball.velocity = Vector2.zero;
        _ballInstance = Instantiate(_ball);
    }
    private void Launch()
    {
        float minAngle = 0;
        float maxAngle = 180;

        float angle = Random.Range(minAngle, maxAngle);
        float radians = angle * Mathf.Deg2Rad;
        
        
        float xSpeed = Mathf.Cos(radians) * BaseSpeed;
        float ySpeed = Mathf.Sin(radians) * BaseSpeed;
        _ballInstance.velocity = new Vector2(xSpeed,ySpeed);
    }
    private IEnumerator Delay()
    {
        yield return new WaitForSeconds(SpawnMovementDelay);
        Launch();
    }
}

I think you just have to increase your Acceleration value in Launch() and to add it to your ball.

public float Acceleration;
private void Start()
{
    Acceleration = 0;
}
private void Launch()
{
    ...
    Acceleration += 1; //Can be less
    _ballInstance.velocity = new Vector2(xSpeed,ySpeed) + Acceleration;
}