Proper Method to Redirect

I'm having trouble doing a redirect to a named route. Here is my routing.yml and controller code:

bncreports.user_doc_upload:
  path: "/user-doc-upload"
  defaults:
    _controller: '\Drupal\bncreports\Controller\FileController::userDocUpload'
    _title: "User Documents"
  requirements:
    _role: "administrator+bnc_operator"

...
bncreports.delete_file:
  path: "/delete-file"
  defaults:
    _controller: '\Drupal\bncreports\Controller\FileController::delete'
  requirements:
    _role: "administrator+bnc_operator"
...

class FileController extends ControllerBase
{
...

public function delete(Request $request): Response
  {
    $path = trim(urldecode($request->query->get('path')));
    $route = trim(urldecode($request->query->get('route')));

    if (file_exists($path)) {
      unlink($path);
      \Drupal::messenger()->addMessage("$path has been deleted");
    } else
      \Drupal::messenger()->addMessage("Cannot find $path", 'error');

    return $this->redirect($route);
  }

...
}

{{ form }}

<br><br>
<p><strong>{{ path }}</strong></p>

<table>
	<tr>
		<th>Name</th>
		<th>Size</th>
		<th>Modified</th>
		<th></th>
	</tr>
  {% for item in content %}
		{% if (item != "." and item != "..") %}  
		<tr>
			<td><a href="/download-file?path={{ path|url_encode }}{{ "/"|url_encode }}{{ item|url_encode }}">{{ item }}</a></td>
			<td>{{ filesize("#{path}/#{item}") }}</td>
			<td>{{ filemtime("#{path}/#{item}")|date("m/d/Y h:ia") }}</td>
			<td><a href="/delete-file?path={{ path|url_encode }}{{ "/"|url_encode }}{{ item|url_encode }}&route=bncreports.user_doc_upload">delete</a></td>
		</tr>
	  {% endif %}
  {% endfor %}
</table>

I get a Page Not Found and the browser's url has xxxxxx/bncreports.user_doc_upload

I'm confused. Why is the route name in the url? This should work. The path in bncreports.user_doc_upload which is /user-doc-upload works  fine.