Are you using an outlook.com account or Microsoft 365 business account?
Support information: https://learn.microsoft.com/microsoft-365/admin/get-help-support?view=o365-worldwide&WT.mc_id=M365-MVP-6934
For a business account:
If you are unable to log into the account because you don't have another authentication method, you will need to contact your admin to update your information or temporarily disable MFA.
If you are the only admin and can't log into your account or the admin portal, you'll need to call Microsoft support for help. They should connect you with the data protection team and after you verify your identity, will reset your account.
Call during your country's business hours. If you get the phone bot (and not immediately told to use the admin portal) make sure you ask for the data protection team and say "I cannot access admin center and I am the only admin user".
The numbers are in this article: Contact business support
You will need to contact the Microsoft Data Protection team for assistance with this issue. Due to security and confidentiality reasons, our community team members do not have the necessary permissions or tools to access any user's tenant information. The Data Protection team is specifically equipped to handle these matters, verify the required information, and take the appropriate action to resolve your issue.