This is the most efficient and scalable way to automatically configure Android VPN clients on ChromeOS devices with the correct hostname:

Obtain Configuration: Get the required VPN configuration details (hostname, authentication methods, etc.) from the VPN provider or your organization's network administrator. This configuration is typically in JSON format.

Create Managed Configuration: In the Google Admin console, navigate to Devices > Chrome > Settings > Android Apps > Managed Configurations.

Select the VPN App: Choose the specific Android VPN app you want to configure.

Add JSON Configuration: Paste the JSON configuration into the provided field. Ensure the configuration is valid and accurate.

Save and Deploy: Save the managed configuration and apply it to the desired organizational units (OUs) containing the ChromeOS devices.

This method allows you to centrally manage VPN configurations for Android apps on ChromeOS devices, ensuring consistency and reducing the manual effort required from users.