How do you reduce jittering for gyroscope control system?

This is a simplified version of my gyro-controlled camera with a sensitivity modification (a side effect of increasing sensitivity is that the jitteriness is exacerbated).

 public class GyroControl : MonoBehaviour
 {
     
     private Transform _rawGyroRotation;
     Vector3 gyroAdjust;
     [SerializeField] private float _smoothing = 0.1f;
 
     void Start()
     {
         Input.gyro.enabled = true;
         Application.targetFrameRate = 60;
 
         _rawGyroRotation = new GameObject("GyroRaw").transform;
         _rawGyroRotation.position = transform.position;
         _rawGyroRotation.rotation = transform.rotation;
 
     }
 
     private void Update()
     {
         _rawGyroRotation.rotation = Input.gyro.attitude;
 
         gyroAdjust = _rawGyroRotation.rotation.eulerAngles * 2; //increase rotation sensitivity
         transform.rotation = Quaternion.Euler(gyroAdjust);
 
         transform.rotation = Quaternion.Slerp(transform.rotation, _rawGyroRotation.rotation, _smoothing);
 
     }
 }

When in motion, the jittering isn't noticeable. But when you hold the phone still, there's what I assume to be just analogue noise that causes jittering. The controller is based off a controller I got from here: https://gist.github.com/kormyen/a1e3c144a30fc26393f14f09989f03e1 . That controller I linked doesn't have a multiplied by 2 Euler like I do (increases sensitivity ) but the jittering is still present in that version just not as bad.

I would really appreciate any help or advice on how to add a filter or something to reduce the jittering for this kind of controller. Thanks.