Hello Anon_378,
Welcome to the Microsoft Community.
I understand that you mentioned unsolicited one-time codes. Could you please clarify if they are frequent and numerous?
You can refer to the following information regarding this situation. Additionally, you can log in to this link to check if there have been any unusual login activities recently.
You can also refer to the section on troubleshooting unsolicited codes in the following link.
Troubleshooting verification code issues - Microsoft Support
If you have any concerns, you can let me know.
Best Regards,
Jimmy.W - MSFT| Microsoft Product Support Community