0. https://www.mailboss.com/mailboxes-federal-property/
I've interacted with many government offices and very few of them set up their DNS, SSL certificates and servers properly. It seems like just the other day I had to explain to the DMV that RFC1918 addresses must not be in their MX records. They argued with me. And you don't even want to know which agencies can't install their SSL certificates correctly. Not saying names, they do not handle embarrassment very well.
You establish your own domicile, and you receive your mail at no charge to you.
You establish your own email address, and you receive email at no charge to you
There are so many free email services why would this even be needed.