Slowing down an object progressively 2D

I’m trying to make a slide mechanic and I’ve had some trouble figuring out how to slow down the velocity of a character, I want it to progressively slow down and I thank you all in advance. BTW its a top down shooter if that helps and I have no gravity on my rigidbody. Also I’m pretty shit with IEnumerators so that may be why I’m having this problem. Also if the code is messed up because theres no breaks I’m sorry I’m new to the forums

`private Rigidbody2D myRb;

public float moveSpeed;

public bool isSliding;
public float slideSpeed;

void Update () {
if (Input.GetKey(right) || Input.GetKey(down) || Input.GetKey(up) || Input.GetKey(left))
{
if (Input.GetKey(right) && !isSliding)
{
//myRb.velocity = new Vector2(moveSpeed, 0);
transform.Translate(new Vector3(moveSpeed * Time.deltaTime, 0f, 0f));
transform.localScale = new Vector3(1f, 1f, 1f);
GunRotator.instance.offset = 0;
lastMove = 1;
}
if (Input.GetKey(left) && !isSliding)
{
//myRb.velocity = new Vector2(-moveSpeed, 0);
transform.Translate(new Vector3(-moveSpeed * Time.deltaTime, 0f, 0f));
transform.localScale = new Vector3(-1f , 1f , 1f);
GunRotator.instance.offset = -180;
lastMove = 2;
}
if (Input.GetKey(up) && !isSliding)
{
//myRb.velocity = new Vector2(0, moveSpeed);
transform.Translate(new Vector3(0f, moveSpeed * Time.deltaTime, 0f));
lastMove = 3;
}
if (Input.GetKey(down) && !isSliding)
{
//myRb.velocity = new Vector2(0, -moveSpeed);
transform.Translate(new Vector3(0f, -moveSpeed * Time.deltaTime, 0f));
lastMove = 4;
}
}
else if(!isSliding)
{
myRb.velocity = new Vector2(0, 0);
}

if (Input.GetKey(slide))
{
isSliding = true;
//This is what I have tried
myRb.velocity *= 0.8f;
moveSpeed = slideSpeed;
moveSpeed *= slideSpeed;
}
else
{
isSliding = false;
}
}`

You shouldn’t mix physics and transform based movements. If you have a rigidbody you can give it a force opposite to it’s velocity direction in FixedUpdate. Use ForceMode.Force with AddForce. To realistically slow down an object it needs to have mass, so don’t forget about that either.