How do I get the HTTP Status Code from an Exception thrown in Laravel?

If you look at the source code of Symfony\Component\HttpKernel\Exception\NotFoundHttpException you will find that it extends Symfony\Component\HttpKernel\Exception\HttpException if you look at the declaration of the class you will see that $statusCode is private but it has a getter method

class HttpException extends \RuntimeException implements HttpExceptionInterface
{
    private $statusCode;
    private $headers;

    public function __construct(int $statusCode, string $message = null, \Throwable $previous = null, array $headers = [], ?int $code = 0)
    {
        $this->statusCode = $statusCode;
        $this->headers = $headers;

        parent::__construct($message, $code, $previous);
    }

    public function getStatusCode()
    {
        return $this->statusCode;
    }
    //...
}

As such you simply need to do $exception->getStatusCode() to retrieve the status code (404 in your case) though you should do a check to make sure your throwable implements the HttpExceptionInterface because that might not always be the case and so the method would not exist and you would get a fatal error

if ($exception instanceof \Symfony\Component\HttpKernel\Exception\HttpExceptionInterface) {
  $code = $exception->getStatusCode();
}