How to stop Google from blocking my attempts to login to my own account?

I'm attempting to login to an old account (non-gmail address; I own the domain) that I setup on Google years ago. I still have the password as that is saved in my password manager. However, Google is blocking my attempts to login as they don't recognize the device/IP address. Understandable since I last logged in while I was living in a different country.

I've gone through their recovery process and can answer everything except the phone code as I no longer have that phone number. I can even confirm the email code that they send as my email is hosted elsewhere. However, Google still says that they cannot confirm that I own my account. I even get emails from Google warning me:

> Someone just used your password to try to sign in to your account. Google blocked them, but you should check what happened.

Of course, I cannot check if I cannot login.

I know a lot of people run into this same problem with no resolution unless someone inside Google helps. So I'm asking here. Does anyone know how I can recover access?