Agreed with Mia. In the USA, you need to do a status match through National to get 5-star.

So signup for National status through the AMEX website. Wait for the National emails on status and number.

Then go start a Hertz membership, and there's a Hertz website that details what you need to provide to status match (National #, screenshot, etc.).

Whole process probably takes about 30 minutes to set up.

Also Hertz 5-star, the first time you rent, you must still go to the counter. Subsequent times, your car will be waiting for you.