Can you set a serialized value to start with?

I have an object I want to instantiate and I want it to take on a value. The serialized field I made is just so that I could put in a game object to reference location for respawning. I’d like to assign a value to a object even if it can only be modified in code.

In code, how could I write something to fill a value into the serialized fields I showed in the picture?

Script:

using UnityEngine;

public class Ball : MonoBehaviour
{
    [SerializeField] public Transform RespawnPoint;
    // config parameter

    [SerializeField] float pushX = 0.1f;
    [SerializeField] float pushY = 10f;
    [SerializeField] float randomFactor = 0.2f;
    [SerializeField] float LowRandomFactor = -0.2f;


    TrailRenderer MyBallTrail;
    // cached component references
    Rigidbody2D rb;

    private bool hasStarted = false;


      

    void Start()
    {
        // rigidbody to rb
        rb = GetComponent<Rigidbody2D>();
        MyBallTrail = GetComponent<TrailRenderer>();
    }

    // Update is called once per frame
     void Update()
    { // ball lock & stick
        if (!hasStarted)
        {
            LockBallToPaddle();
            LaunchOnClick();
            MyBallTrail.time = 0f;
        }
        else if (hasStarted){
            MyBallTrail.time = 0.2f;
        }
        Debug.Log("Your boolean hasStarted is set to " + hasStarted);
    }
    public void LaunchOnClick()
    {
        if (Input.GetKeyDown("space"))
        {
            hasStarted = true;
            GetComponent<Rigidbody2D>().velocity = new Vector2(pushX, pushY);
          
        }
    }

   public void LockBallToPaddle()
    {
        Vector2 paddlePos = new Vector2(RespawnPoint.transform.position.x, RespawnPoint.transform.position.y);
        transform.position = paddlePos;
    }

    private void OnCollisionEnter2D(Collision2D collision)
    {
      Vector2 velocityAdjustment = new Vector2
            //X axis
            (Random.Range(LowRandomFactor,randomFactor),
            //Y axis
            Random.Range(0, randomFactor));
        if (hasStarted)
        {
            rb.velocity += velocityAdjustment;
        }
        else if (collision.transform.CompareTag("DeathBarrier"))
        {
            hasStarted = false;
        }
    }
    public void ResetPosition()
    {
        hasStarted = false;
        Vector2 paddlePos = new Vector2(RespawnPoint.transform.position.x, RespawnPoint.transform.position.y);
        transform.position = paddlePos;
    }
}

EDIT: I actually ended up replacing the paddle1 variable and updated the script. I only need to fill a single value to respawn the object at this point, so one serialized field. Thanks!!!

Do you mean at editor time? Implement the void Reset(); method.

Do you mean at runtime? Check in Awake() if the values are acceptable, and if not either 1) complain loudly with Debug.LogError() and/or Debug.Break();, or 2) set the values to some reasonable defaults in Awake.