O botão não se move (Segui as instruções já passadas)

Boa noite pessoas, tudo bem? Gente eu tentei praticamente todas as respostas as questões levantadas com o mesmo assunto. O botão não se move de jeito nenhum, nem colocando manualmente as directions. Segue os cód:

XML:

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    android:layout_width="match_parent"
    android:layout_height="match_parent">

    <ListView
        android:id="@+id/activity_main_lista_de_alunos"
        android:layout_width="match_parent"
        android:layout_height="match_parent">

        <com.google.android.material.floatingactionbutton.FloatingActionButton
            android:id="@+id/floatingActionButton3"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_alignParentEnd="true"
            android:layout_alignParentBottom="true"
            android:layout_marginEnd="26dp"
            android:layout_marginBottom="26dp"
            android:clickable="true"
            android:tint="#F12E65" />
    </ListView>

</RelativeLayout>

MANIFEST:

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
    package="alura.com.agenda">

    <application
        android:allowBackup="true"
        android:icon="@mipmap/ic_launcher"
        android:label="@string/app_name"
        android:roundIcon="@mipmap/ic_launcher_round"
        android:supportsRtl="true"
        android:theme="@style/Theme.Agenda">
        <activity android:name=".MainActivity">
            <intent-filter>
                <action android:name="android.intent.action.MAIN"/>
                <category android:name="android.intent.category.LAUNCHER"/>
            </intent-filter>
        </activity>
    </application>

</manifest>

MAIN:

package alura.com.agenda;

import android.app.Activity;
import android.os.Bundle;
import android.view.View;
import android.widget.ArrayAdapter;
import android.widget.ListView;
import android.widget.TextView;
import android.widget.Toast;
import androidx.annotation.Nullable;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.List;

public class MainActivity extends Activity {
    @Override
    protected void onCreate(@Nullable Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        List<String> alunos = new ArrayList<>(Arrays.asList("Bruna", "Sandra", "Chloe", "Cleonice", "Jenny"));
        ListView listaDeAlunos = findViewById(R.id.activity_main_lista_de_alunos);
        listaDeAlunos.setAdapter(new ArrayAdapter<>(this, android.R.layout.simple_list_item_1,
                alunos));



    }
}

O que eu faço?