Processes in Microsoft 365 for setting up Office apps, redeeming product keys, and activating licenses.
Hello, Tom Meagher1.
Welcome to Microsoft Community. Regarding the issue you mentioned about the device re-asking for activation. We would like to clarify that. Regardless of the activation method, the Office product activation process requires communication with a Microsoft server to verify your subscription information and download the activation code. If your computer is out of reach of the Microsoft servers or has an unstable internet connection, the activation may fail.
Our previous thread mentioned the phone activation method:
Office 2021 offline activation - Microsoft Community
The phone activation method only requires a manual call to customer service, but it still requires an internet connection during the verification process. Therefore, you may need to re-activate the program while you are online, thanks again for your understanding and support.
Best Regards,
Airy.C - MSFT | Microsoft Community Support Specialist