Hey there! Nice to meet you!
I'm sorry you are experiencing this.
The only way to recover a hacked account is through the official Microsoft troubleshooter guide:
If you didn't receive the results from the account recovery webform, please try submitting another request via Incognito/InPrivate window and using different devices and network services. Then please check your email inbox, junk, and spam folders.
If the account recovery web form doesn't work, and since the security info has been replaced by the hacker, I'm afraid there is no other working method to recover the Microsoft account, and Microsoft Support cannot help either.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