Cannot delete Entra ID tenant — MSA-owned tenant, Graph API returns 400, "Microsoft Internal" SPs block deletion

I'm unable to delete my Entra ID tenant and have exhausted all self-service options. Documenting the full situation in case it helps others.

Root situation: I created an Azure Free account using a personal Gmail-linked Microsoft Account (MSA). This created an Entra tenant where my identity is represented as username_gmail.com#EXT#@tenantname.onmicrosoft.com — a guest proxy object rather than a native organizational account. I believe this MSA/tenant identity mismatch is the root cause of all issues below.

What I've tried:

az ad sp list --all shows ~19 service principals, all returning "Specified App Principal ID is Microsoft Internal" when deletion is attempted via az ad sp delete.

Microsoft Graph PowerShell (Connect-MgGraph + Remove-MgServicePrincipal) returns:

This API is not supported for MSA accounts
Status: 400 (BadRequest)

This is the hard blocker — MSA accounts cannot manage service principals via Graph API at all.

The tenant deletion checklist in Entra admin center keeps flagging Enterprise Applications as unresolved despite the Portal's Enterprise Apps list showing zero deletable entries.

Ask: Can a Microsoft engineer force-clean the tenant on the backend? The tenant has no active subscriptions, no resources, no custom app registrations. Everything except the auto-generated Microsoft Internal service principals has been cleared.

Tenant details:

• Directory domain: [redacted for privacy — available to share via DM with Microsoft staff]
• Tenant ID: afd1dcae-ffe5-4c01-8a5f-8cd85847b550
• Account type: Personal MSA (Gmail-linked)