iOS 13: Swift - 'Set application root view controller programmatically' does not work

Question

I have following code in my AppDelegate.swift to setup root view controller for an iOS application. But it does not work. It follows Target structure (defined under General

Answer 1

let controller = ....
let keyWindow = UIApplication.shared.windows.filter {$0.isKeyWindow}.first
keyWindow?.rootViewController = controller
keyWindow?.makeKeyAndVisible()

These are the basic code required to set root view controller.