I want to randomly pick a wave to spawn everytime

 using UnityEngine;
 
 public class BlockSpawner : MonoBehaviour
 {
 public Transform[] spawnPoints;
 
 public GameObject blockPrefab;
 
 public float timeBetweenWaves = 2f;
 private float timeToSpawn = 2f;
 
 void Update()
 {
 if (Time.time >= timeToSpawn)
 {
 spawnBlocks();
 
 timeToSpawn = Time.time + timeBetweenWaves;
 }
 }
 
 void spawnBlocks() // I want to add another one of these and i want it to pick from them
 {
 
 int randomIndex = Random.Range(0, spawnPoints.Length);
 for (int i = 0; i < spawnPoints.Length; i++) // i want to add one like this for (int i =1;i