how to disable file manager applications backing up my android application

Question

my current android application has this application manifest content

  android:dataExtractionRules="@xml/data_extraction_rules"
  android:allowBackup="false"
  android:fullBackupContent="false"

with the data_extraction_rules xml file contents resembling this

<data-extraction-rules>
    <cloud-backup>
        <exclude domain="database" />
        <exclude domain="external" />
        <exclude domain="file" />
        <exclude domain="root" />
        <exclude domain="sharedpref" />
    </cloud-backup>
    <device-transfer>
        <exclude domain="database" />
        <exclude domain="external" />
        <exclude domain="file" />
        <exclude domain="root" />
        <exclude domain="sharedpref" />
    </device-transfer>
</data-extraction-rules>

my android application gradle resembles this

android {
    compileSdkVersion 32
    buildToolsVersion "32.0.0"

    defaultConfig {
        applicationId "org.my.app"
        minSdkVersion 26
        targetSdkVersion 32
        versionCode 3
        versionName "1.3"

        testInstrumentationRunner "androidx.test.runner.AndroidJUnitRunner"
    }

i am expecting that my android application will not be allowed to create any type of backup when its installed on my users device.

however using third party file managers installed on my test devices i am able to create backups of my application.

where is my error? are my expectations incorrect? e.g. the above manifest and xml file contents do not control application backups?

is there no approach i can take that will make it impossible for my application to be backed up?