rabidus-test/Assets/Scripts/ActivateAllDisplays.cs

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

public class ActivateAllDisplays : MonoBehaviour
{
    private void Start()
    {
        Screen.sleepTimeout = SleepTimeout.NeverSleep;
    
        Debug.Log("displays connected: " + Display.displays.Length);
        for (int i = 1; i < Display.displays.Length; i++)
        {
            Display.displays[i].Activate();
        }
    }

    [ContextMenu("Debug")]
    private void NextDisplay()
    {
        Debug.Log($"CurrentScreen: {Display.displays.Length}");
    }
}