I told them I have asthma (I do). I literally just went to the doctor for an episode 3 days ago on Friday. In my state, you are exempt from mask wearing for medical conditions. The government refused to transfer my title and literally screamed at me while I was on the phone to “get out”. (She was black and I’m white and she clearly had an attitude with me from the very beginning).
I’m calling the ADA lawyers tomorrow, I’m bout to be the white “I CANT BREATHE” poster boy.
Pretty sure there is no enforceable law or statutory requirement for you to comply with mask orders or policy. Their building policy is not the same as statutes of law and I don't see how that could possibly trump your right to be in a public building accessing public services.
That said, I dunno if the ADA has any help for you or not and I would assume the DMV has some kind of immunity for the kinds of damages you would like to seek from them.