THIS^^^^. If you're in the Apple ecosystem, and you're not already using another 2FA authenticator app, I recommend using the built-in Passkeys feature. There's a decently written article
here that can help you get going. Passkeys can also be
used on Windows. Supposedly works on Chrome as well. I've also used it to login via FireFox.
I was able to get this set up and working across all my devices within just a few minutes. It works really well.
This is
exactly the sort of problem the mods are trying to address. Your account sounds like a wonderful candidate for a hijacking and exploitation of the TB Classifieds. That you no longer have access to the email address you used to set your account (yahoo, perhaps?), means that someone else who gains access can use the info that's probably still in your old inbox to impersonate you, even taking control of your TB account. ("Free" email accounts are also why using email for 2FA is not a best practice.)
Do what you can to recover access to your email account via security questions, etc, then update your profile to use an email you do control and enable 2FA.