Maybe even US users should consider getting an email service that isn't hosted in the US and protects their privacy.
@tuta.com might be worth looking into and contacting to hear how they respond to these kinds of requests.
Floored by this story. A man wrote a pollite email to a federal prosecutor objecting to the deportation of an Afghan seeking asylum. DHS responded with an administrative warrant to get the man's info from Google, then visited his home to intimidate him.

DHS Hunts Down 67-Year-Old U.S. Citizen Who Criticized Them in Email
The Department of Homeland Security is using a little-known tool to go after its critics.