Hi @Daemetius ,
As far as I know, your need Microsoft account to activate Office 365 and if you want to use Microsoft account to activate Office 365 in personal PC, this more related to the authentication mechanism for account login.
I suggest you post this issue to Microsoft Admin forum to get more help:
https://answers.microsoft.com/en-us/msoffice/forum/msoffice_o365Admin
The reason why we recommend posting appropriately is you will get the most qualified pool of respondents, and other partners who read the forums regularly can either share their knowledge or learn from your interaction with us. Thank you for your understanding.
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