Imprecise analog triggers values

[LollosoSi]

I've noticed the analog trigger values are too imprecise to be used, mine is a classic controller and I am sure these triggers have a better response than the driver shows, cause these work as expected (on a linear scale, 0 to 255) with https://www.arduino.cc/reference/en/libraries/nintendo-extension-ctrl/ where 255 is very close to the full pressure of the trigger

With this driver however, I can see the axis being reported from -128 to 127, but the commutation is basically instant with little values in between, by almost not pressing the trigger. Seems to be worse in high resolution mode.
The full press event (button) is still reported when the trigger is actually fully pressed, while the axis has been "full" for a good part of the button track already.

I would suspect this is just a mistake in the interpretation of the data from the controller