I have downloaded a demo app, which scales fine on my iPhone 12 pro max and fits the whole display. However, on the app I am developing, I cannot for the life of me get my app to scale the whole display.
Here is the a photo of my app which does not take up the full screen.

Here is the devtools window size:

And here is the devtools window size for the demo app, which scales perfectly and fills the whole display:

Notice that the window size is much larger on the demo app. How do I go about changing the size in my app? I tried fitting a constrainedBox, sizeBox, customScrollView but nothing works since it seems to be constrained by the renderObject.
I am new to Flutter, any help is much appreciated.