how to align view at the bottom of the screen but also below other view in relative layout

I added in the top RelativeLayout the attribute alignPatentBottom="true" now your pommes frites should be on the bottom. :) In my emulator everything works fine. Glad to have some feedback if it works?

<?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"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:background="@color/background_color"
    android:paddingTop="@dimen/main_padding"
    android:paddingRight="@dimen/main_padding"
    android:paddingLeft="@dimen/main_padding"
    android:layout_height="match_parent"
    tools:context=".welcomeActivity"
    android:layout_alignParentBottom="true">

    <TextView
        android:id="@+id/textView_welcome"
        android:paddingTop="8dp"
        android:paddingBottom="5dp"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_centerHorizontal="true"
        android:layout_alignParentTop="true"
        android:layout_marginLeft="20dp"
        android:fontFamily="@font/great_vibes"
        android:layout_marginRight="20dp"
        android:background="@drawable/actionbar_background"
        android:gravity="center"
        android:text="@string/who_am_i"
        android:textColor="@color/text_color_white"
        android:textSize="44sp" />

    <LinearLayout
        android:layout_marginTop="50dp"
        android:layout_width="wrap_content"
        android:orientation="vertical"
        android:id="@+id/lisearLayout_welcome"
        android:layout_centerHorizontal="true"
        android:layout_below="@+id/textView_welcome"
        android:layout_height="wrap_content">

        <androidx.cardview.widget.CardView
            style="@style/MyCardView"
            app:cardCornerRadius="40dp"
            android:layout_width="360dp"
            android:id="@+id/customerButton"
            android:layout_height="200dp">

            <RelativeLayout
                android:layout_width="match_parent"
                android:layout_height="match_parent">
                <TextView
                    android:layout_width="wrap_content"
                    android:layout_centerInParent="true"
                    android:text="@string/customer"
                    android:textSize="44sp"
                    android:fontFamily="@font/great_vibes"
                    android:textColor="@color/button_color_black1"
                    android:layout_height="wrap_content"/>
            </RelativeLayout>

        </androidx.cardview.widget.CardView>


        <androidx.cardview.widget.CardView
            style="@style/MyCardView"
            app:cardCornerRadius="40dp"
            android:layout_width="360dp"
            android:id="@+id/employButton"
            android:layout_height="200dp">

            <RelativeLayout
                android:layout_width="match_parent"
                android:layout_height="match_parent">
                <TextView
                    android:layout_width="wrap_content"
                    android:layout_centerInParent="true"
                    android:text="@string/employ"
                    android:fontFamily="@font/great_vibes"
                    android:textSize="44sp"
                    android:textColor="@color/button_color_black1"
                    android:layout_height="wrap_content"/>
            </RelativeLayout>

        </androidx.cardview.widget.CardView>

    </LinearLayout>


    <ImageView
        android:id="@+id/image_welcome"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_below="@+id/lisearLayout_welcome"
        android:layout_alignParentBottom="true"
        android:layout_marginTop="5dp"
        android:layout_marginBottom="0dp"
        android:src="@drawable/ic_french_fries" />


</RelativeLayout>

Remove android:layout_below="@+id/lisearLayout_welcome" in the ImageView and add android:layout_above="@id/image_welcome" to the LinearLayout.
In this way you are assigning the available space to the LinearLayout, instead in your code you are assigning the available space to the ImageView.

Use something like:

<RelativeLayout>
   <TextView/>
   <LinearLayout
        android:layout_above="@id/image_welcome"
        android:layout_centerHorizontal="true"
        android:layout_below="@+id/textView_welcome">

       <!-- ... -->

  </LinearLayout>

  <ImageView
        android:layout_marginTop="5dp"
        android:id="@+id/image_welcome"
        android:layout_width="wrap_content"
        android:layout_centerHorizontal="true"
        android:layout_alignParentBottom="true"
        android:src="@drawable/..."
        android:layout_height="wrap_content"/>

</RelativeLayout>

Apply different orientation in the LinearLayout using vertical in portrait mode, and horizontal in landscape mode.