drecon-unity/Assets/8_Scripts/2_General/RotationOffset.cs

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

public class RotationOffset : MonoBehaviour
{
    private float m_Speed = 2.5f;
    private void FixedUpdate()
    {
        transform.RotateAround(transform.parent.transform.position, Vector3.up, m_Speed *  Time.fixedDeltaTime);
    }
}