Vector3 direction = transform.forward;
float distance = 1f;
float stopDistance = 0.5f;

RaycastHit hit;

if (Physics.Raycast(transform.position, direction, out hit, distance))
{
    if (hit.collider.CompareTag("Enemy"))
    {
        float distanceToEnemy = Vector3.Distance(transform.position, hit.collider.transform.position);

        if (distanceToEnemy < stopDistance)
        {
            rb.velocity = Vector3.zero;
        }
        else
        {
            Vector3 avoidDirection = Vector3.Reflect(direction, hit.normal);
            rb.AddForce(avoidDirection * moveForce);
        }
    }
    else
    {
        rb.AddForce(direction * moveForce);
    }
}