//controller

class ExampleController extends GetxController{
    //your code
    List<StatelessWidget> screens(ExampleController controller){
        return [AScreen(
        controller: controller,
      ),
      BScreen(
        controller: controller,
      ),
      CScreen(
        controller: controller,
      ),
      DScreen(
        controller: controller,
      ),];
    }
}
//Child Screen
class AScreen extends StatelessWidget{
final ExampleController controller;
  const AScreen({
    Key? key,
    required this.controller,
  }) : super(key: key);

  //rest of the code
}

//Parent Screen
class ParentScreen extends StatelessWidget{
    final _controller = Get.put(ExampleController());
    //bla bla bla
    //i am writing only scaffolds body part
    body: IndexedStack(
        children: _controller.screens(_controller),
        index: //put your index,
        );
}