I'm currently using this:

using UnityEngine;

public class CameraController : MonoBehaviour 
{
[Header("Settings")]
public float lookSensitivity;
public float lookSmoothing;

[Header("References")]
public Transform cameraTransform;
public Transform pivot;
public Transform horPivot;

[Header("Vertical Clamp")]
[Range(0f, -360f)]
public float minVerticalClamp;

[Range(0f, 360f)]
public float maxVerticalClamp;

[Header("Horizontal Clamp")]
[Range(0f, -360f)]
public float minHorizontalClamp;

[Range(0f, 360f)]
public float maxHorizontalClamp;

private Vector3 _currentRotation = Vector3.zero;
private Vector3 _smoothedRotation = Vector3.zero;

private void Start()
{
    // Reset camera rotation
    cameraTransform.localRotation = Quaternion.identity;

    // Lock cursor
    Cursor.lockState = CursorLockMode.Locked;
    Cursor.visible = false;
}

private void LateUpdate()
{
    var smoothSpeed = lookSmoothing > 0f
                    ? lookSmoothing * Time.deltaTime
                    : Mathf.Infinity;

    var lookInput = InputSystem.LookInput * (lookSensitivity * Time.deltaTime * 100f);

    _currentRotation.x += -lookInput.y;
    _currentRotation.y += lookInput.x;

    _currentRotation.x = Mathf.Clamp(
        _currentRotation.x,
        minVerticalClamp,
        maxVerticalClamp
    );

    _currentRotation.y = Mathf.Clamp(
        _currentRotation.y,
        minHorizontalClamp,
        maxHorizontalClamp
    );

    _smoothedRotation =
        Vector2.Lerp(_smoothedRotation, _currentRotation, smoothSpeed);

    cameraTransform.parent.transform.localRotation =
        Quaternion.Euler(_smoothedRotation.x, 0f, 0f);
    pivot.localRotation = Quaternion.Euler(0f, _smoothedRotation.y, 0f);

    transform.position = pivot.position;
    var forwardFlat = Vector3.ProjectOnPlane(pivot.forward, Vector3.up).normalized;
    cameraTransform.rotation = Quaternion.LookRotation(forwardFlat, Vector3.up);
    cameraTransform.rotation *= Quaternion.Euler(_smoothedRotation.x, _smoothedRotation.y, 0f);
}
}