Filter by ACF Field

I am trying to create a custom filter to find a custom post by a custom field value. Currently I have having trouble getting the GraphiQL IDE to return any results based on stopNumber in the following structure.

query QueryStop {
  sgstops(where: {stopNumber: 171}) {
    nodes {
      guideFields {
        stopNumber
      }
      id
      title
    }
    edges {
      node {
        slug
        title
        id
        content
        guideFields {
          stopNumber
        }
      }
    }
  }
}

I have added the following code to my functions.php but I seem to be missing something. I based the code of the tutorial I found here. https://www.wpgraphql.com/2020/04/14/query-posts-based-on-advanced-custom-field-values-by-registering-a-custom-where-argument

add_filter('graphql_post_object_connection_query_args', function ($query_args, $source, $args, $context, $info) {

	$stop_id = $args['where']['stop_number'];

	if (isset($stop_id)) {

		$query_args['meta_query'] = [
				[
					
						'key' => 'stop_number',
						'value' => $stop_id,
						'compare' => '='
				]
		];
}
	

	return $query_args;
}, 10, 5);