Using Classic Outlook on Windows for personal email, calendar, and contact management
Hey there. Nice to meet you.
If the email you mentioned is an unfamiliar email address, this means that your Microsoft account was compromised. The hacker was able to remove the account's primary email address/security info and replace it with their own email address.
Since the security info has been replaced by the hacker, I'm afraid there is no other working method to recover the Microsoft account, and Microsoft Support cannot help either.
Thank you for your understanding.
Best regards,
Darhyl