Displaying Splash Screen for Longer Than Default Seconds

Displaying splash screen for longer than default seconds

No, the default.png is shown while your app starts up.

You can add a new viewcontroller which will display the default.png in the application didFinishLoading.

This way you display the default.png a bit longer.

You should only show the default.png if you are loading data, which could take some time.
As the appstore guidelines state, you should not delay starting of you are any longer than necessary.

iOS: how to delay the launch screen?

You can create a view controller that uses the LaunchScreen storyboard, present it (not animated) on applicationDidFinishLaunching or applicationWillFinishLaunching, and dismiss it whenever you want.

Keep in mind this is discouraged by Apple because it gives the impression that your app takes a lot longer to launch, which is bad user experience and might cause some of your users to delete your app.

How can I delay splash launch screen programmatically in Swift Xcode iOS

Put one line of code in AppDelegate class -

func application(_ application: UIApplication, didFinishLaunchingWithOptions launchOptions: [UIApplicationLaunchOptionsKey: Any]?) -> Bool {
        Thread.sleep(forTimeInterval: 3.0)
        // Override point for customization after application launch.
        return true
    }