Use this to change the {admin_email} for all Gravity Forms Admin Notifications

change-admin-email.php

<?php 

//copy everything below this line

add_filter( 'gform_notification', 'change_notification_email', 10, 3 );
function change_notification_email( $notification, $form, $entry ) {
 
    if ( $notification['name'] == 'Admin Notification' ) {
 
        // toType can be routing or email
        $notification['toType'] = 'email';
        $notification['to'] = 'email@example.com'; //put your TO email address here
        $notification['from'] = 'email@example.com'; //put your FROM email address here
    }

    return $notification;
}