how to make objects to spin(orbit) around a point on 2 axes?

You can just parent it to the first object or attach t$$anonymous$$s script to the 2 object with the same value

 using UnityEngine;
 
 public class Rotator : MonoBehaviour
 {
 
     [SerializeField]
     private float speed = 10.0f;
 
     [Range(-1,1)]
     [SerializeField]
     private int direction = -1;
 
     [SerializeField]
     private Vector3 axis = Vector3.up;
 
     [SerializeField]
     private float angle = 10.0f;
 
     // Update is called once per frame
     private void Update()
     {
         transform.rotation *=  Quaternion.Euler( axis * angle * speed * Time.deltaTime * direction) ;
     }
 }