GPS accuracy of iPhone Xs with iOS 15.1 - is 3metres about right?

Does anyone know the iPhone specification with respect to relative accuracy of an iPhone XS running up-to-date iOS15.1 software?

For example, relative to the iPhone's 'true' location, how innately accurate is the GPS accuracy of the microchip inside the iPhone XS? For example, I've read in an earlier Apple Discussion post that back in 2012, an iPhone of that day possessed GPS accuracy within 3metres of it's true location.

https://discussions.apple.com/thread/4187946?answerId=19204685022#19204685022

Would a 2019-era iPhone XS be better (i.e. 1metre), worse or about the same 3 metres?

While I understand that environmental variables such a heavy cloud cover and dense tree foliage, plus the positioning of and number of orbiting satellites used by any iPhone can negatively affect accuracy, I am interested in finding an Apple sanctioned value as far as GPS accuracy is concerned.

I'd appreciate knowing if there are any Apple bulletins that cite specific performance characteristics. Cheers!