Hello Andrea
Here is a suggestion: create an Airtable database linked to your ERP if possible, or create an entirely new database in accordance with your ERP for the application. Also, check if your ERP can be directly used with Bravo Studio. This information will be linked to each automatically generated user ID.
To implement this with Airtable, create a Firebase login page, a profile page with its associated form if you wish, a homepage for the list of services, a details page for detailed information on the services, a one-time usable form page (name, first name, email address, phone number, subscription information) linked to the subscription page and the automatic generation of IDs. Also, add a page to display user subscriptions and a payment page with a WebView (a specific payment link from Airtable for each service).
Regarding Airtable, the subscription table should contain all user subscription information. In Figma, the subscription form page will only contain relevant fields (name, first name, email address, phone number) and a "send" button. By executing this, you will obtain the ID, name, email, and phone number as results. This will allow you to compare them in your ERP and complete the remaining subscription information. Thus, the user will have all their subscription information thanks to the synchronization of the GET LIST with the subscription interface designed in Figma.