Symfony – ID and User-Friendly Routes – SEO

Use case:

• I have data which has both an ID and a ROUTE
• I have a list of links and a router which use the ID so that, if the title or route ever changes, the links will always point to the same content.
• I would like the ROUTE to be displayed in the URL instead of the ID when the user goes to the page for usability and SEO purposes.

Currently, I am using a redirect for this and I doubt that’s the proper way to handle it.

public function show($slug)
{
  $list = array(
    // blog data goes in here
  };
  // when we go to the blog post page, we loop through the blog post data
  foreach ($list as $post) {
    // if the slug from our url is equal to the ID
    if ($slug == $post['id']){
      // redirect to the user-friendly route instead
      $route = '/blog/' . $post['route'];
      return $this->redirect($route);
    }
    // if this is the user-friendly, route, then render the page
    if ($slug == $post['route']) {
        $title = $post['title'];
        $content = $post['content'];
    }
  }
  // hello/show.html.twig is the twig template I'm currently using to render single pages
  return $this->render('hello/show.html.twig', [
    'title' => $title,
    'content' => $content,
  ]);
}   

This technically works, but I really don’t think it’s the actual correct method. Is there a better way of using two routes for the same view and giving preferential treatment to one route over another somewhere between the link click and the page render?