How to change the default routing behavior when entering a new URL through address bar in a flutter web app? (using getx) - flutter

Question

I am working on a Flutter Web App using Getx for navigation and state management. One of the routes in my flutter app has two query parameters. Let us call these parameters Dataset and Index. When the Dataset parameter is changed through the URL, I want to make an API call to retrieve the new dataset, and when the Index parameter is changed, I want to display the data from the dataset at that particular index on the app. Index in this case is an observable RxInt variable defined in the controller.
However, the default behavior when I change the URL and press enter is for the Flutter app to push a new page on to the navigation stack. The behavior I prefer is to simply update the values and make a new API call if necessary. The API call may be done by simply refreshing the page since it is handled by the Getx controller onInit function.
I'm not very familiar with how routing in flutter works and I haven't found a solution to change the behavior for routing itself. I've tried a few ways to update the values despite pushing the new page on to the stack, such as setting the value for index through the initState or build calls on my widgets but those changes aren't visible on my UI. I've also tried reinitializing the controller by deleting it but that didn't work either.
EDIT: I have added a code example:
Widget:
class MainscreenView extends StatefulWidget {
const MainscreenView({Key? key}) : super(key: key);
#override
State<MainscreenView> createState() => _MainscreenViewState();
}
class _MainscreenViewState extends State<MainscreenView> {
late MainscreenController mainscreenController;
#override
Widget build(BuildContext context) {
return GetX<MainscreenController>(
init: MainscreenController(),
initState: (_) {
mainscreenController = Get.find<MainscreenController>();
},
builder: (_) {
return Scaffold(
body: Center(
child: Text(
'Current index is ${mainscreenController.index.value}',
style: const TextStyle(fontSize: 20),
),
),
);
});
}
}
Controller:
class MainscreenController extends GetxController {
final index = 0.obs;
late String? dataset;
#override
void onInit() {
super.onInit();
final String? datasetQuery = Get.parameters['dataset'];
if (datasetQuery != null) {
dataset = datasetQuery; //API call goes here
} else {
throw Exception('Dataset is null');
}
final String? indexString = Get.parameters['index'];
if (indexString == null) {
throw Exception('Index is null');
} else {
final int? indexParsed = int.tryParse(indexString);
if (indexParsed == null) {
throw Exception('Index Cannot be parsed');
} else {
index.value = indexParsed;
}
}
}
}
The initial route is /mainscreen?dataset=datasetA&index=0. If I were to modify the route in the address bar to /mainscreen?dataset=datasetA&index=5 for example and press enter, The current behavior of Flutter is to push a new page onto the navigation stack. I would like to update the value of index instead and display it on the same page, but I haven't found a way to accomplish this. Also, if dataset parameter is updated I would like to again avoid pushing a new page onto the stack and refresh the current page instead so that the onInit function is run again and the API call is made automatically.