Discontinue Qt Purchasing API, instead move to OS specific samples using target OS native purchasing features.
Supporting Purchasing through Qt API has couple of major drawbacks; Implenting proper e2e security is impossible or difficult. Secondly, purchasing features on Windows, macOS, iOS and Android has big differences and an abstraction API is not easy / feasible to implement. Code once and deploy everywhere does not really work on this domain.
Therefore a better approach, direct use of native API from Qt is required.
Create and release target OS specific sample application s utilizing native Purchasing features from a Qt application.
The samples can be released independently from each other and in priority order: Android, iOS, Windows, macOS.