@klabuschagne

As per the linked change record, symfony-cmf/routing has been deprecated. The solution is to change the reference to \Drupal\Core\Routing\RouteObjectInterface.
https://www.drupal.org/node/3151009 →

I was able to work around the issue on my local instance by changing line 176 of the january.theme file to:

  if ($route = $request->attributes->get(\Drupal\Core\Routing\RouteObjectInterface::ROUTE_OBJECT)) {
    $title = \Drupal::service('title_resolver')->getTitle($request, $route);
    $variables['page__title']=strip_tags($title);
  }