Apple does not support UISplitViewController.DisplayMode.PrimaryOnly as splitViewController.preferredDisplayMode

Question

How can enable the masterViewController as UISplitViewController.preferredDisplayMode (UISplitViewController.DisplayMode.PrimaryOnly) on higher-end iPhone devices (such as iPhone 14 Plus) in landscape mode?

I am utilizing a splitView with the style .doubleColumn. My objective is to have the splitView present the MasterView as the initial screen and the DetailedView as the subsequent screen in landscape mode, resembling the default iPhone portrait mode, specifically on higher-end iPhone devices (such as iPhone 14 Plus and iPhone Pro Max). If launched on an iPad, it should be displayed as 'side by side' ('oneBesideSecondary').

How can we display the MasterViewController using splitViewController.preferredDisplayMode, specifically setting it to UISplitViewController.DisplayMode.PrimaryOnly when rotated to landscape mode on iPhone higher end devices? However, it's important to note that Apple does not support UISplitViewController.DisplayMode.PrimaryOnly.

Desired UI: iPhone Portrait:

PrimaryVC:

https://i.stack.imgur.com/cqWbH.png

secondaryVC:

https://i.stack.imgur.com/8x7Ps.jpg

iPhone Landscape:

primaryVC:

https://i.stack.imgur.com/3dCwP.png

seconddaryVC:

https://i.stack.imgur.com/bBe4O.png

iPad:

portrait:

https://i.stack.imgur.com/PfXTW.jpg

Landscape:

https://i.stack.imgur.com/teqV0.jpg

Here is my code :

class ViewController: UIViewController , UISplitViewControllerDelegate {
        
    var splitVC = UISplitViewController(style: .doubleColumn)
   
    var delegateProtocol : TableSelectionDelegate?
    var ListView : ListViewController!

    override func viewDidLoad() {
        super.viewDidLoad()
       
        splitVC.delegate = self
        splitVC.presentsWithGesture = true
        splitVC.preferredSplitBehavior = .tile
        ListView = ListViewController()        
    }
    
    override func viewWillAppear(_ animated: Bool) {
        
        var primaryVC : ListViewController = UIStoryboard(name: "Main", bundle:nil).instantiateViewController(withIdentifier: "ListViewController") as! ListViewController
        var secondVC : SecondViewController = UIStoryboard(name: "Main", bundle: nil).instantiateViewController(withIdentifier: "SecondViewController") as! SecondViewController

        primaryVC.delegate = self
        
      
        secondVC.view.backgroundColor = UIColor.placeholderText
        
        if UIDevice.current.userInterfaceIdiom == .pad
        {
            splitVC.setViewController(primaryVC, for: .primary)
            splitVC.setViewController(secondVC, for: .secondary)
            splitVC.preferredDisplayMode = UISplitViewController.DisplayMode.oneBesideSecondary
        }
        else
        {
            splitVC.setViewController(secondVC, for: .primary)
            splitVC.setViewController(primaryVC, for: .secondary)
            splitVC.preferredDisplayMode =   UISplitViewController.DisplayMode.secondaryOnly
            
            // hide back btn to primary list
            let controllers = splitVC.viewControllers
            
            primaryVC = (controllers[controllers.count-1] as! UINavigationController).topViewController
            as!  ListViewController
            
            primaryVC.navigationItem.leftBarButtonItem =
                           splitVC.displayModeButtonItem
            primaryVC.navigationItem.leftItemsSupplementBackButton = false
        }
       
        addChild(splitVC)
        splitVC.view.frame = CGRect(x: 0, y: 0, width: UIScreen.main.bounds.size.width, height: UIScreen.main.bounds.size.height)
        self.view.addSubview(splitVC.view)
        splitVC.didMove(toParent: self)
      
    }
    
    
    func splitViewController(_ svc: UISplitViewController, willChangeTo displayMode: UISplitViewController.DisplayMode) {
        if UIDevice.current.userInterfaceIdiom == .phone
        {
            svc.presentsWithGesture = displayMode != .secondaryOnly
        }
    }
}

extension ViewController : TableSelectionDelegate
{
    func selectedRow(row: Int, viewController: UIViewController) {
      
        splitVC.showDetailViewController(viewController, sender: self)
       
    }
}

I attempted the code above by swapping the PrimaryVC with .secondary and the SecondaryVC with .primary in the splitView for the iPhone device type. As a result, I achieved the desired UI.

splitVC.setViewController(secondVC, for: .primary)
splitVC.setViewController(primaryVC, for: .secondary)
splitVC.preferredDisplayMode = UISplitViewController.DisplayMode.secondaryOnly

However, I'm uncertain whether this approach was correct or incorrect. What would be the best approach to achieve my desired UI?