Lots to unpack there. Yes, GPS does provide PNT.
https://www.transportation.gov/pnt/what-positioning-navigation-and-timing-pnt
However each cellular provider may provide a slightly different interface (or implementation) of PNT.
Plus different parts of the world implement the standards in different ways.
It might be a dox of some kind to explicitly address PNT imprecision - as it may point to provider or locale.
With that said, I do track the delta using the NOAA solar weather site.