Unable to retrieve body from wp_remote_post request to a WP rest api registered route

I am trying to make a simpole post request to a registered route using the following method:

// inside a function that registers the rest route
$namespace = 'marketplace/v1';
$route = 'one_image';

register_rest_route($namespace, $route, array(
 'methods' => WP_REST_Server::CREATABLE,
 'callback' => [$this, 'one_image'],
));

//inside a function

...

$args = array(
 'method' => 'POST',
 'headers'  => array(
  'Content-type: application/x-www-form-urlencoded'
 ),
 'sslverify' => false,
  'body' => array(
  'this' => 'should show in response'
 )
);

$response = wp_remote_request($url, $args);
...


public function one_image(\WP_REST_Request $request) {
 $params = $request;
 $response = new WP_REST_Response($params);
 return rest_ensure_response($response); <--- this just returns an empty object
}

Why are my body arguments not being returned in the response?