I'm working on a downhill racer and I want to have the camera shake to various degrees to convey that the player is getting faster. Right now I have a GameObject called "CameraHolder" which is a parent to the Main Camera.

I have a script attached to the Holder that follows the player, and another script attached to the camera that is meant to shake it within that holder.

CameraHolder Follow Script

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

public class CameraFollow : MonoBehaviour
{
    public Camera cam;
    public Transform player;
    public Vector3 offset;
    public float speed = 2f;
    public Rigidbody rb; 
    public float startingFieldOfView = 60f;

    void FixedUpdate()
    {
        float interpolation = speed * Time.deltaTime;

        Vector3 cameraPosition = new Vector3(Mathf.Lerp(transform.position.x, player.position.x, interpolation), player.position.y + player.localScale.y + offset.y, player.position.z + -player.localScale.z + offset.z);
        
        // Change of camera FOV depending on the speed of the rigidbody
        transform.position = cameraPosition;
       
        cam.fieldOfView = Mathf.Lerp(cam.fieldOfView, startingFieldOfView + (rb.velocity.magnitude / 3), .1f);

CameraShake Script attached to child Main Camera

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

public class CameraShake : MonoBehaviour
{
    public Rigidbody player;
    public float shakeThreshold;
    public float shakeMagnitude;

    private void Update()
    {
        float x = Random.Range(-shakeMagnitude, shakeMagnitude);
        float y = Random.Range(-shakeMagnitude, shakeMagnitude);
        if (player.velocity.magnitude >= shakeThreshold)
        {
            transform.localPosition = new Vector3(x, y, transform.position.z);
        }
    }
}

I think maybe I misunderstand how localPosition works. I thought that it would move the camera the random amount while moving within the holder, but it does nothing. Am I applying this wrong or is the logic off?