Once Google has your phone on one account it is on all of them, and that number is usually already tied to a real person, and Google is often the first place investigators go, and creating a new account without handing them one is now close to impossible. The two-phone workaround does not survive either -- same tower, same WiFi, or one contact who has both numbers is enough to join them. You do the only right thing: no Google account at all, and no number that is yours sitting on anything you care about.
Once Google has your phone on one account it is on all of them, and that number is usually already tied to a real person, and Google is often the first place investigators go, and creating a new account without handing them one is now close to impossible. The two-phone workaround does not survive either -- same tower, same WiFi, or one contact who has both numbers is enough to join them. You do the only right thing: no Google account at all, and no number that is yours sitting on anything you care about.