Hi @likwid welcome to the forums.
Yes, although most of the above functionality that you laid out would need to be handled by your own application. Square can handle the subscriptions part through the Subscriptions API, but the rest would be up to you as far as I can tell. For example, you can use the Subscriptions API to create the subscription for a customer, but the widget allotment would need to be tracked/counted by your own integration. Furthermore, the QR code piece would also need to be handled by your own integration. Square’s API will be able to tell you if the subscription exists and has been paid for, but beyond that you would need to handle the rest.
Please let me know if I misunderstood or if you have additional questions!