I hope Shopify builds this solution on the admin without having to use a 3rd party app. It takes third party apps processing time to update the stock resulting in overselling and other issues. Makes me really miss WooCommerce. If you found any apps that work well for high volume please let me know. Stock adjustments need to happen in real time, and batching in 5 minutes or taking 1-3 minutes to update stock under race conditions is not scalable.