Is this solution using queryRef to call start/stopPolling methods still working? Maybe I implemented it wrong, though seems similar to yours

//component
      queryRef: QueryRef<unknown> = this.scanQueueService.getImagesScanQueue();
      this.queryRef.startPolling(500);

//service
  getImagesScanQueue() {
    return this.apollo.watchQuery({
      query: getImagesScanQueue(),
      fetchPolicy: 'network-only',
    });
  }