Is it possible to overlay a zoomed image (InteractiveViewer) on top of all existing objects - even the status bar?

child: InteractiveViewer(
 transformationController: controller,
 maxScale: 2.0,
 minScale: 2.0,
 child: imageBig,
 fit: BoxFit.fitWidth,
),

Did you manage to solve it?

Of course you can, above all but the StatusBar. You could hide it, but that will change the size of the screen and make some weird effects for the user. But if you don’t use a SafeArea widget, the InteractiveViewer will extend behind the StatusBar and remain seen.