Rotating object - make program select one value and rotate the object by this value.

Hi! So I have this code to rotate an object by a certain random value:

 using System.Collections;
 using System.Collections.Generic;
 using UnityEngine;
 
 public class Cube : MonoBehaviour
 {
     public MeshRenderer Renderer;
   
     public Vector3 position = new Vector3(3, 4, 1);
     public Vector3 scale = new Vector3(1, 1, 1);
     public float scaleCoefficient = 1.3f;
     public Color color = new Color(0.5f, 1.0f, 0.3f, 0.4f);
     private float rotationInterval = 1f;
     void Start()
     {
         transform.position = position;
         transform.localScale = scale * scaleCoefficient;
         
         Material material = Renderer.material;
         
         material.color = color;
     }
     
     void Update()
     {
          int rotationX = Random.Range(-11, 11);
      float rotationY = 0f;
      float rotationZ = 0f;
     transform.Rotate(rotationX * Time.deltaTime, rotationY * Time.deltaTime, rotationZ * Time.deltaTime);
     }
 }

But it seems that the program selects a different value every second, so my object doesn't rotate but jitters in place while the program selects random numbers between minus and plus values. What can I do to make the program select one value and rotate the object by that value at the start of the scene?