Flutter – PageController not working while putting it inside GetxController

I am building a flutter application and now I am working on the on boarding page. I am using Getx for state management and logic. In the on boarding screen I have a PageView.builder which returns the pages of the on boarding page with a horizontal scrolling axis. I also used smooth page indicator. My page controller is in the OnBoardingController which extends GetxController. When I scroll and move to other pages the page indicator is not being updated.

My next button is also not working it gives an error that says: ScrollController attached to multiple scroll views.

Here is where I used the pageController from GetxController code:

class OnBoardingPage extends StatelessWidget {
  const OnBoardingPage({super.key});

  @override
  Widget build(BuildContext context) {
    final OnBoardingPageController onBoardingPageController =
        Get.put(OnBoardingPageController());
    return Scaffold(
      /* <-------- Content --------> */
      body: SafeArea(
        top: false,
        child: Stack(
          children: [
            /// Center right bubble
            Positioned(
              top: 270,
              right: -100,
              child: Image.asset(AppAssetImages.lightBubbleTr),
            ),

            /// Top left bubble
            Positioned(
              top: -110,
              left: -120,
              child: Image.asset(AppAssetImages.blueBubbleTl),
            ),

            /// Introduction pages
            PageView.builder(
              controller: onBoardingPageController.pageController,
              onPageChanged: onBoardingPageController.updatePageIndicator,
              scrollDirection: Axis.horizontal,
              itemCount: OnboardingPageContents.onboardingContents.length,
              itemBuilder: (context, index) {
                /// Single intro screen data
                final introContent =
                    OnboardingPageContents.onboardingContents[index];
                /* <---- Single Intro screen widget ----> */
                return
                IntroContentWidget(
                    imagePath: introContent.imagePath,
                    slogan: introContent.slogan,
                    subtitle: introContent.subtitle);
              },
            ),

            /// Current Page Dot Indicator
            Positioned(
              left: 0,
              right: 0,
              bottom: AppDeviceUtility.getBottomNavigationBarHeight() + 25,
              child: Center(
                child: SmoothPageIndicator(
                  controller: onBoardingPageController.pageController,
                  count: OnboardingPageContents.onboardingContents.length,
                  axisDirection: Axis.horizontal,
                  effect: ExpandingDotsEffect(
                    dotHeight: 15,
                    dotWidth: 15,
                    spacing: 5,
                    expansionFactor: 3,
                    activeDotColor: AppColors.primaryColor,
                    dotColor: AppColors.darkColor.withOpacity(0.2),
                  ),
                ),
              ),
            )
          ],
        ),
      ),

      /// Next Button
      floatingActionButton: FloatingActionButton(
        shape: const CircleBorder(),
        foregroundColor: Colors.white,
        backgroundColor: AppColors.primaryColor,
        onPressed: () {
          onBoardingPageController.nextPage();
        },
        child: const Icon(
          Icons.keyboard_arrow_right,
          size: 35,
        ),
      ),
    );
  }
}

Here is the on boarding controller code:

class OnBoardingPageController extends GetxController {
  static OnBoardingPageController get instance => Get.find();

  // Variables
  final PageController pageController = PageController();
  final RxInt currentIndex = 0.obs;

  // Update current index when page scrolls
  void updatePageIndicator (index) => currentIndex.value = index;

  // Next button function
  void nextPage () {
    if(currentIndex.value == OnboardingPageContents.onboardingContents.length - 1){
      Get.to(() => ContinueWithGooglePage());
    } else {
      int page = currentIndex.value + 1;
      pageController.jumpToPage(page);
    }
  }

The pageController works if I use a simply use a pageController in the same class and the page indicator updates, but I want to use Getx. I also have issue with the next button. I have put the right codes but it still doen’s work. Please check the above code.