extension

fun FragmentActivity.currentFragmentOnTop(): Fragment? {
    try {
        val host = supportFragmentManager.findFragmentById(R.id.navHostFragment) as NavHostFragment
        return host.childFragmentManager.fragments.getOrNull(0)
    } catch (ignored: IllegalStateException) {
    } catch (e: Exception) {
        e.log()
    }
    return null
}

Fragment.kt

class SettingsListFragment : BaseFragment(), 
    OnBackPressListener {



    override fun onBackPress(): Boolean {
//        findNavController().navigate(R.id.authorizations_list)
        findNavController().popBackStack()
        return true
    }

MainActivity.kt

    override fun onBackPressed() {
        val onBackPressListener = currentFragmentOnTop() as? OnBackPressListener
        if (onBackPressListener?.onBackPress() != true) super.onBackPressed()
    }

nav_graph.xml

    <fragment
        android:id="@+id/settingsListFragment"
        android:name="com.saltedge.authenticator.features.settings.list.SettingsListFragment"
        android:label="SettingsListFragment">

        <action
            android:id="@+id/authorizations_list"
            app:popUpTo="@id/authorizationsListFragment" />
    </fragment>