Mobile app with web dashboard and multiple roles

I am looking to develop a mobile app with a web dashboard that works on both iOS and Android platforms. Functionality Overview: Admin: Admin will have full control over the application, including adding and managing products. Admin sets the initial product details. Customer: Customers will log in using their phone numbers. Upon logging in, they have the option to choose whether they want to become a seller or remain a customer. Seller: Sellers can access a product management screen where they can modify product prices, quantities, and types of weights for the products added by the admin. Buying: Customers can switch to the buying mode from the main screen. They can search for a specific seller by entering the seller's number, ID, or using a QR code. Once they select a seller, they can view the seller's available products from the seller's inventory. Statistical Screen: There should be a statistical screen showing product prices based on daily fluctuations (whether they are low or high). Prices should be determined based on each seller's inventory. Free Trial and Subscription: The app can offer a certain number of free trial days determined by the admin. Afterward, users are prompted to subscribe on a monthly basis. Notifications: After a successful transaction between a seller and a customer, both parties should receive notifications. These notifications can include details of the transaction, such as the items purchased, the total cost, and any delivery information. Invoice Section: Within the app, there should be a dedicated section for invoices. In this section, customers can view a history of their past purchases and invoices. Sellers can also access invoices related to their sales. Returns: To handle returns, you can implement a returns functionality. Customers should have the ability to initiate a return request for specific products they are not satisfied with or for damaged items. Sellers can then review and approve or reject return requests. If approved, the customer can return the product, and a refund or replacement process can be initiated. The admin dashboard must have all the information: the number of registered users and the number of transactions. Price information by day, month, year, with graphs. And also control roles. On the seller's dashboard, you can view the number of sales transactions and monthly income. For each role there will be properties