I know you are making stuff up as I own a Tesla and live on the East coast and FSD is nowhere close to what you are describing. You can barely use FSD 4 months out of the year.
With the latest Tesla Updates I can tell it thinks there's a grade or curve issue that is causing it to brake; but before the latest update it would just randomly brake in certain places (coming down from 70 to 40 very quickly) and that is just dangerous in the DC area.