WillPopScope is the correct way to do this.
(it seems too complicated… it should be easier… like a setting on the root app).
It is not complicated. It’s a one liner :
WillPopScope(
onWillPop: () async => false,
child: <children here>
)
A configuration file would make things more complicated as it’s harder to read and maintain.
And remember that in flutter everything is a widget not just half of them. Authentification, configurations, everything.