Hi, I hope you are doing good.
I understand your requirement and happy to let you know that I have a readymade solution for grocery app.
I have ready android and iOS app for customer to view product, category, apply basic sorting and filter, see details, cart management, place and track order status.
Along with this I will happy to provide store admin, from where you can manage inventory.
Please reply me to discuss in details. I can help you to ready your store within a week.