Managing personal Outlook.com account settings, security, and privacy
It seems my secondary email was hacked, and it hasn't even been 30 days
Did you have Two Step Verification enabled for the account? If not, do it if you recover this account or when you create a new one.
https://support.microsoft.com/en-us/accounts-billing/security/how-to-use-two-step-verification-with-your-microsoft-account
For the hacked account: Start with any suggestions from the Account Sign-In Helper
- In a Private/Incognito browser session, open: https://aka.ms/sign-in-helper
- Scroll down to "Choose how you normally sign in, then enter your details"
- Click "With an email address"
- Enter your email address and click [OK]