Which access method does NOT allow enforcement of policy controls on iOS devices by Google Workspace?

The method that does not allow the enforcement of policy controls on iOS devices through Google Workspace is the process of adding an account type of "Google" through Mail, Calendar, and Contacts. This approach essentially allows users to configure their Google account within the native iOS applications for email, calendar, and contacts. While it provides access to Google services, it does not integrate with the mobile device management (MDM) capabilities that are necessary for enforcing administrative policies, settings, or security measures on the device itself.

In contrast, utilizing the Google Admin app or configuring with Apple Configurator involves direct integration with Google Workspace's management features, allowing for the application of specific policies, remote management, and security configurations. These methods support a level of device control essential for organizational governance. Setting up a G Suite account manually on iOS could also restrict certain capabilities and lacks the MDM benefits essential for enforcing comprehensive policy controls. Thus, the choice of adding an account type through Mail, Calendar, and Contacts stands out as the only method that fails to enable such policy enforcement.