Custom REST Endpoint In Plugin

I am working on an application that serves an Angular app in a WP plugin. The flow works like so:

-User answers questions in a brief survey on the Angular front-end, which makes a POST request to the WP custom POST endpoint with the survey answers.

-The callback function attached to the WP POST endpoint takes those answers, filters them (the plugin is essentially a Woocommerce product filter), and returns a filtered product list.

-The Angular app makes a GET request to the WP endpoint, and renders that filtered product list.

I’m doing something wrong, because all the parts are working individually: The Angular HTTP requests, filtering logic, and custom endpoints (when tested via Insomnia or with hard-coded arguments) are doing what they’re supposed to when tested in isolation, but when I test the app out in staging, the render just silently fails.

I’m pretty new to WordPress, but I’ve pored over the REST API docs, and they left me with a LOT of questions, namely:

-How do I test this setup and ensure that the proper request data is indeed reaching the endpoint?

-Am I doing this correctly? Should I have separate POST and GET logic, or is just having the POST more than enough? My code looks like this:

add_action('rest_api_init', function() {
  register_rest_route('awe/v1', '/awesomeproducts', array(
    'methods' => 'POST',
    'callback' => 'get_awesome_params',
    'args' => array(),
    'permission_callback' => function () {
      return true;
    }
  ));
});

function get_awesome_params( WP_REST_Request $request ) {
  $parameters = $request->get_params();

  // Very long filtering logic takes the $parameters and turns it
  // into $finalProducts, an array of objects

  return new WP_REST_Response($final_products, 200);
}

I’ve spent a lot of time looking for ansers on here, Stack Overflow, WordPress Stack Exchange, etc. Any help would be greatly appreciated.