To regain access to your Microsoft 365 tenant after losing your only Global Admin account, you will need to follow the identity verification processes outlined by Microsoft. Since you are ready to add a TXT record for domain verification, here are the steps you should take:
- Confirm Domain Ownership: You need to verify that you own the domain by adding a TXT record to your domain registrar. The verification process typically requires you to add a specific TXT record provided by Microsoft.
- Submit a Support Request: If you are unable to access your account, you can submit a support request to Microsoft. Go to the Microsoft 365 support page, select "I can't sign in or access my tenant," and follow the prompts to verify your identity and ownership of the organization. You may need to provide billing details and organization information as part of this process.
- Contact IT Partner: If a Microsoft partner created or manages your tenant, you should reach out to their support team for assistance in recovering access.
Unfortunately, I cannot initiate the domain verification process for you, but following these steps will help you regain access to your account.