Hi @Zero Nine ,
Unfortunately this is not possible as of now.
Device CreationTime is stored in deviceSystemMetadata and deviceKey attributes of the device, which are not exposed via Graph API version (api-version=1.6) used by PowerShell. This information is exposed via Graph API (api-version=1.61-internal), which is used by Azure Portal. This is why you can see the CreationTime on Azure Portal but not via PowerShell.
You may post a feedback regarding this at our feedback portal.
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