I would like to turn off my two-factor authentication

If you have used 2 factor authorization for more than two weeks you cannot turn it off. If it has been less than two weeks go back to the email you received when it was activated and click on the link in the email to turn it off.

This is a user-to-user technical support site operated by Apple, no one is going to email you.

All networks should be able to support it, if not they are completely wide open networks that are unsafe anyway. Regardless, there is no way to turn it off and I doubt there ever will be. You could quit using your current Apple ID and create a new one and don't turn on 2 factor with that one.

Keep using 2 factor authorization. After 2 weeks there is no way to turn it off.

First off, this is a user-to-user technical support site, I don't work for Apple. Second, 2 factor authorization has nothing to do with your telephone number it is based upon your Apple ID.