How to properly stretch /anchor two images in a kotlin app (android)

Question

I would like to create an app in android studio using kotlin. In one of my activities there is a background image (blue) and a circle image (red). I want the background to stretch to screen sizes of different devices. (see image below) This means the circle sometimes gets smaller relative to the background.

Is there a way to adjust the circle size automatically and to keep it centered? As you see I tried with

 android:background="@drawable/background"

and was also playing around with

android:scaleType="fitXY"

But it didnt work out. Any help is greatly appreciated! Thank you.

<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:background="@drawable/background"
tools:context=".MainActivity">

<ImageView
    android:id="@+id/background"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:src="@drawable/background"
    app:layout_constraintStart_toStartOf="parent"
    app:layout_constraintTop_toTopOf="parent"
    android:layout_marginStart="100dp"
    android:layout_marginTop="200dp"/>

<ImageView
    android:id="@+id/circle"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:src="@drawable/circle"
    app:layout_constraintStart_toStartOf="parent"
    app:layout_constraintTop_toTopOf="parent"
    android:layout_marginStart="100dp"
    android:layout_marginTop="200dp"/>

</androidx.constraintlayout.widget.ConstraintLayout>

I added the two images for testing: