IEnumerator MoveRandomPos()
    {
while(true){

yield return null;


        RaycastHit hit;
        Ray ray = new Ray(transform.position, Quaternion.Euler(0f, Random.Range(0f, 360f), 0f) * transform.forward);

        /*Debug.DrawRay(transform.position, ray.direction, Color.red, 3f);*/

        if (Physics.Raycast(ray, out hit))
        {
            if (hit.distance > 2f)
            {
                yield return StartCoroutine(MoveToPos(ray.direction));
                yield return new WaitForSeconds(Random.Range(4f, 7f));
            }
        }
}
    }

IEnumerator MoveToPos(Vector3 direction){
nav.SetDestination(direction);
var startPos = nav.transform.position;
var randomDistance = Random.Range(4f, 7f);
yield return new WaitUntil(()=> Vector3.Distance(startPos, nav.position) >= randomDistance);
}