I drive a lot. If you leave that much space at 80 miles an hour at least two vehicles will immediately fill it
Leave the space - better some other idiot gets the bad karma than you. I’ve been driving semi trucks for over 22 years and will simply slow down when someone rides too close to my back end.
On Washington 290 east of Spokane they painted lines across the road and posted signs “Three lines is safe distance.” It’s really helpful to establish safe following distance.
It’s a two-lane 55 mph road.