Anything that reduces (or more commonly eliminates) exhaust gas recycling relative to fueling and air flow will increase NOX emissions even at very moderate throttle openings. I challenge you to find a remap that proprtionally increases exhaust gas recycling, Molgrips.
Ok, on a purely technical tangent:
Remaps increase the fuel and air delivered at any given throttle opening. But power is proportional to fuel and air being burned in the cylinder. So to travel at a given speed you only need a certain amount of fuel and air.
Reducing EGR at low load wouldn’t do anything for your performance, as far as I can tell? It might reduce your smoke and increase NOx, but I don’t think it would increase power. But even if it did the driver would lift off to travel the same speed, so you’d end up simply recalibrating the pedal effectively.
Remapping increases the maximum available power when your foot is down, but driving along at the same speed requires the same power whatever your engine map.
I am not an engine mapper though so I could be wrong.