What I have read about the new EPA future emissions NOx requirements
leads me to conclude that no gasoline, diesel fuel, propane or methane internal combustion engine can meet them.

A hydrogen powered internal combustion engine might, but even that is iffy, without DEF injection.

Vehicles are hit with this NOx limitation,
but fixed nitrogen agricultural fertilizer Urea can be legally applied on ground in a nearly unlimited manner,
and that releases NOx into the planet’s same air.

Is sauce for the goose also sauce for the gander?

Not at the EPA.

Science it is not.

I spent 6 years thinking literally half my waking hours about fuel cell science funded by a US Department of Energy grant.
(during sleep part of my brain must have continued pondering Gibbs energy)

The trailer behind your EV to extend its highway range
to be future NOx legal
likely must have a hydrogen/pure oxygen fueled fuel cell,
which were on Apollo spacecraft.