Usually a license purchased by the Microsoft store is assigned as a digital license, linked to your Microsoft account.
See the documentation below:
In the meantime try to perform the steps below and see if you will find provide the Windows key.
To find the Windows key:
Follow the steps below:
Product key via Command Prompt.
Click the Windows key + X.
Select Command Prompt (Admin).
Enter the command below to find your product key. Don't forget to press Enter
wmic path softwareLicensingService get OA3xOriginalProductKey
Write down the code.
If still problem exist, please have a chat with MS
https://partner.support.services.microsoft.com/en-us/contactus/windows/tech-services/
Hope this helps.
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