how to clear all backstack after moving to new activity with Navigation Graph

Question

I have several fragments, when the user has completed the onboarding stage he will be redirected to the MainActivity page. But when I want to enter the MainActivity page, the onboarding fragment appears for a few moments. How to fix it?

The problem like that

My launcher_nav.xml (Navigation)

<?xml version="1.0" encoding="utf-8"?>
<navigation xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools"
    android:id="@+id/launcher_nav"
    app:startDestination="@id/splashScreenFragment">

    <fragment
        android:id="@+id/splashScreenFragment"
        android:name="com.ryz.nutrilicious.presentation.splashscreen.SplashScreenFragment"
        android:label="fragment_splash_screen"
        tools:layout="@layout/fragment_splash_screen" >
        <action
            android:id="@+id/action_splashScreenFragment_to_onBoardingFragment"
            app:destination="@id/onBoardingFragment"
            app:enterAnim="@android:anim/fade_in"
            app:exitAnim="@android:anim/fade_out"
            app:popEnterAnim="@android:anim/fade_in"
            app:popExitAnim="@android:anim/fade_out"
            app:popUpTo="@id/splashScreenFragment"
            app:popUpToInclusive="true" />
        <action
            android:id="@+id/action_splashScreenFragment_to_mainActivity"
            app:destination="@id/mainActivity"
            app:enterAnim="@android:anim/fade_in"
            app:exitAnim="@android:anim/fade_out"
            app:popEnterAnim="@android:anim/fade_in"
            app:popExitAnim="@android:anim/fade_out"
            app:popUpTo="@id/splashScreenFragment"
            app:popUpToInclusive="true" />
    </fragment>
    <fragment
        android:id="@+id/onBoardingFragment"
        android:name="com.ryz.nutrilicious.presentation.onboarding.OnBoardingFragment"
        android:label="fragment_on_boarding"
        tools:layout="@layout/fragment_on_boarding" >
        <action
            android:id="@+id/action_onBoardingFragment_to_introFragment"
            app:destination="@id/introFragment"
            app:enterAnim="@android:anim/fade_in"
            app:exitAnim="@android:anim/fade_out"
            app:popEnterAnim="@android:anim/fade_in"
            app:popExitAnim="@android:anim/fade_out"
            app:popUpToInclusive="true" />
    </fragment>
    <activity
        android:id="@+id/mainActivity"
        android:name="com.ryz.nutrilicious.presentation.MainActivity"
        android:label="activity_main"
        tools:layout="@layout/activity_main" />
    <fragment
        android:id="@+id/introFragment"
        android:name="com.ryz.nutrilicious.presentation.onboarding.IntroFragment"
        android:label="fragment_intro"
        tools:layout="@layout/fragment_intro" >
        <action
            android:id="@+id/action_introFragment_to_mainActivity"
            app:destination="@id/mainActivity"
            app:enterAnim="@android:anim/fade_in"
            app:exitAnim="@android:anim/fade_out"
            app:popEnterAnim="@android:anim/fade_in"
            app:popExitAnim="@android:anim/fade_out"
            app:popUpTo="@id/launcher_nav"
            app:popUpToInclusive="true" />
    </fragment>
</navigation>

IntroFragment.kt

class IntroFragment : Fragment() {

    private var _binding: FragmentIntroBinding? = null
    private val binding get() = _binding
    private val onBoardingViewModel: OnBoardingViewModel by viewModel()

    override fun onCreateView(
        inflater: LayoutInflater, container: ViewGroup?,
        savedInstanceState: Bundle?
    ): View? {
        _binding = FragmentIntroBinding.inflate(inflater, container, false)
        return binding?.root
    }

    override fun onViewCreated(view: View, savedInstanceState: Bundle?) {
        super.onViewCreated(view, savedInstanceState)

        binding?.apply {
            btnLetsStarted.setOnClickListener {
                //onBoardingViewModel.saveState(true)
                findNavController().navigate(R.id.action_introFragment_to_mainActivity)
            }
        }
    }

    override fun onDestroyView() {
        super.onDestroyView()
        _binding = null
    }
}

OnBoardingFragment.kt

class OnBoardingFragment : Fragment() {

    private var _binding: FragmentOnBoardingBinding? = null
    private val binding get() = _binding
    private var pos = 0

    override fun onCreateView(
        inflater: LayoutInflater, container: ViewGroup?,
        savedInstanceState: Bundle?
    ): View? {
        _binding = FragmentOnBoardingBinding.inflate(inflater, container, false)
        return binding?.root
    }

    override fun onViewCreated(view: View, savedInstanceState: Bundle?) {
        super.onViewCreated(view, savedInstanceState)

        val fragmentList = arrayListOf(
            FirstScreenFragment(),
            SecondScreenFragment(),
            ThirdScreenFragment()
        )

        val adapter = ViewPagerAdapter(
            fragmentList,
            requireActivity().supportFragmentManager,
            lifecycle
        )

        binding?.apply {
            onBoardingViewPager.adapter = adapter
            onBoardingViewPager.getChildAt(0).overScrollMode = RecyclerView.OVER_SCROLL_NEVER
            layoutIndicator.dotsIndicator.attachTo(onBoardingViewPager)

            onBoardingViewPager.registerOnPageChangeCallback(object : OnPageChangeCallback() {
                override fun onPageSelected(position: Int) {
                    super.onPageSelected(position)
                    pos = position

                    if (pos == fragmentList.size - 1) {
                        layoutIndicator.btnNext.setOnClickListener {
                            findNavController().navigate(R.id.action_onBoardingFragment_to_introFragment)
                        }
                    }
                }
            })

            layoutIndicator.btnNext.setOnClickListener {
                if (pos < fragmentList.size) {
                    pos++
                    onBoardingViewPager.currentItem = pos
                }
            }
        }
    }

    override fun onDestroyView() {
        super.onDestroyView()
        _binding = null
    }
}

I've done it by adding a script

binding?.apply {
    btnLetsStarted.setOnClickListener {
        //onBoardingViewModel.saveState(true)
        findNavController().navigate(R.id.action_introFragment_to_mainActivity)
        activity?.finish()
    }
}

in IntroFragment.kt, is there any other solution?