Microsoft account: recovery denied after takeover, Authenticator TOTP keys were cloud-backed to the compromised account.

My personal Microsoft account was taken over by an attacker. They changed the security info, and recovery through the account.live.com/acsr form has been denied. I received an email from Microsoft confirming the account was compromised, stating there is no recourse to restore the security settings, and advising me to create a new account, which I have now done, using the same email address, as instructed.

I understand the account itself is probably unrecoverable, but that's NOT what this question is about.

I use Microsoft Authenticator for Android, with cloud backup enabled, tied to the compromised account. That backup includes the TOTP shared secrets for dozens of my third-party accounts (email, financial, servers, etc). The account binding has visibly changed: when I open Authenticator's recovery/sync settings, it now prompts to sign in as an email address that is not mine, matching the attacker's address that account recovery now routes to.

This is extremely serious. Leaving a compromised account active when that account is the anchor for a cloud-backed set of authentication secrets is a significant security gap. I'd like this escalated to someone who can actually address it rather than the automated recovery loop. I am willing to pay for service, if that's what it takes to resolve this security concern.

Troubleshooting already completed

• Completed the compromised-account recovery form (account.live.com/acsr) and denied.
• Received Microsoft's email confirming compromise and stating no restoration is possible.
• Created a new Microsoft account per that email's instruction.
• Began re-registering 2FA on affected third-party accounts through each service's own recovery path. I've prioritized the most sensitive, but it's going to take days to get through all of them.
• Do I need to be concerned with the security on my Windows computers? Are my hard drives in danger of being locked with Bitlocker and held for ransom?

Environment

Personal (consumer) Microsoft account. Account used for Microsoft Authenticator for Android with cloud backup enabled on the compromised account. Account also used with Windows, OneDrive, Minecraft.

Thank you for any assistance you can provide.