Great question — answering as the UphillTech team:
You have to store the cart details locally in app data and publish Remove cart details if order paid success So it will be realtime If you exit the app And reopen it get the cart details
Full answer by Afojet: https://stackoverflow.stackexchange.com/a/79831583 (CC BY-SA 3.0).
Need it done for your business? UphillTech.