Change reading order of elements within a focusable ViewGroup

I have some screens in my app where TalkBack does not infer the correct reading order. According to the documentation, I can use android:accessibilityTraversalAfter and friends to alter the reading order. But it does not work for me for elements within a focusable ViewGroup that should be read together.

The entire layout looks like that:

<?xml version="1.0" encoding="utf-8"?>
<androidx.constraintlayout.widget.ConstraintLayout 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:layout_width="match_parent"
    android:layout_height="match_parent"
    android:accessibilityTraversalBefore="@id/before"
    android:focusable="true"
    tools:context=".MainActivity">

    <TextView
        android:id="@+id/before"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:accessibilityTraversalAfter="@id/before"
        android:text="Before"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintLeft_toLeftOf="parent"
        app:layout_constraintRight_toRightOf="parent" />

    <TextView
        android:id="@+id/after"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:accessibilityTraversalBefore="@id/after"
        android:text="After"
        app:layout_constraintBottom_toTopOf="@+id/before"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toTopOf="parent" />

</androidx.constraintlayout.widget.ConstraintLayout>

It renders After in the middle of the screen, Before at the bottom. I want TalkBack to treat the entire screen as a single contiguous element, hence I set android:focusable to true. By default, TalkBack reads: "After, before". But I want it to read "Before, after". Although I've added android:accessibilityTraversalBefore and android:accessibilityTraversalAfter, it still reads "After, before". That's the output of the Node Tree Debugging:

TreeDebug: (-2147455381)429.FrameLayout:(0, 0 - 1080, 1920):A
TreeDebug:   (30189)429.TextView:(42, 101 - 397, 172):TEXT{My Application}:A:supportsTextLocation
TreeDebug:   (31150)429.ViewGroup:(0, 210 - 1080, 1794):Fa:focusable:accessibilityFocused
TreeDebug:     (33072)429.TextView:(499, 951 - 581, 1002):TEXT{After}:A:supportsTextLocation
TreeDebug:     (32111)429.TextView:(485, 1743 - 595, 1794):TEXT{Before}:A:supportsTextLocation

What am I doing wrong?

Just for completeness: minSdkVersion is 26, targetSdkVersion is 29.

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