The apple developer docs mentions that multiple instances of a scene are available on iOS 13 (ie both iPhone and iPad)
From their developer docs:
In iOS 13 and later, the user can create and manage multiple instances of your app's user interface simultaneously, and switch between them using the app switcher. On iPad, the user can also display multiple instances of your app side by side. Each instance of your UI displays different content, or displays the same content in a different way. For example, the user can display one instance of the Calendar app showing a specific day, and another showing an entire month.
I have tried it on iPadOS and I am able to create multiple scene instances using the gesture and UI actions mentioned in their WWDC videos but I have not found any reference around how to achieve that on iPhone, it would be really helpful to know how to achieve this or whether it is possible or not.