Hi there, Have you tried using mobile device management (MDM) ?
And what is the exact GPO that you used ?
You can use Group Policy settings or mobile device management (MDM) to configure the behavior of Windows Update on your Windows 10 devices. You can configure the update detection frequency, select when updates are received, specify the update service location and more. Manage additional Windows Update settings https://learn.microsoft.com/en-us/windows/deployment/update/waas-wu-settings
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