Basic Wp_user_query not finding any users

the most basic wordpress user query […] is displaying that it has
not found any users

You’re passing an empty array of query arguments and there’s an explicit check for that in the WP_User_Query constructor:

 /**
  * PHP5 constructor.
  *
  * @since 3.1.0
  *
  * @param null|string|array $query Optional. The query variables.
  */
 public function __construct( $query = null ) {
      if ( ! empty( $query ) ) {
           $this->prepare_query( $query );
           $this->query();
     }
}

so that would explain why you get no results in your basic example.