Change the z rotation of my player?,how to adjust the z rotation of my player?

Hello, i am very new to unity, programming and C#. I have a small game set up where there is a player object in a river, and rocks spawn above and move straight down. when the player colides with the rocks, they rotate. since im going with a “Canoe” vibe i like this, but i want the canoe to slowly correct itself like its being paddled by a person. i was thinking a statment that checks if the canoe is the default rotation (in this case 180 degrees) and if it isnt issues a rotation force to correct it. any advice is appreciated, thanks!

public float speed = 15.0f;

public float maxVelocity = 4.0f;

private Vector2 screenBounds;

// Start is called before the first frame update
void Start()
{
    screenBounds = Camera.main.ScreenToWorldPoint(new Vector3(Screen.width, Screen.height, Camera.main.transform.position.z));
}

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

    //PlayerMoveKeyboardwasd();

    if (transform.position.y < -screenBounds.y)
    {
        Destroy(this.gameObject);
    }
    //where im trying to get the rotation
    if (gameObject.transform.rotation.eulerAngles.z < 180)
    {
        
    }

    if (gameObject.transform.rotation.eulerAngles.z > 180)
    {
     
    }

}
//Moving With Arrow keys
void PlayerMoveKeyboard()
{
    //force that pushes the player
    float force = 0.0f;
    //Max Velocity Of The Player
    float velocity = Mathf.Abs(GetComponent<Rigidbody2D>().velocity.x);
    //Get Horizonal Velocity
    float h = Input.GetAxis("Horizontal");

    if (h > 0)
    {
        if (velocity < maxVelocity)
        {
            force = speed;
        }

    }
    else if (h < 0)
    {
        if (velocity < maxVelocity)
        {
            force = -speed;
        }
    }
    GetComponent<Rigidbody2D>().AddForce(new Vector2(force, 0));
}
//Moving with WASD (Unfinished)
void PlayerMoveKeyboardwasd()
{
    float force = 0.0f;
    float velocity = Mathf.Abs(GetComponent<Rigidbody2D>().velocity.x);

    if (Input.GetKey(KeyCode.A))
    {

    }
    if (Input.GetKey("d"))
    {

    }
}

You can use transform.Rotate

You can change rotateamount, the higher the faster it goes.

Example:

Transform.Rotate(0,0,rotateamount)