Driving 80 mph is legal on at least some highways in nine states. Incidentally one of the current speed test cycles (US06), which is included in the EPA range calculation, includes very brief acceleration to 80 mph simulating a highway passing scenario, although the average is only 48 mph.
Test drove yesterday (July 12th) at Rivian Alpharetta after putting in a reservation on the 4th. The demo car I drove was a Glacier White performance, although there was also a Catalina Cove performance in the lot with manufacturer plates so maybe they swap out demo cars; there was also a Half...