Ed's already answered your question about the way the Inspire flies in P-GPS mode when releasing the right stick pitch mode. It requires a very soft touch on the stick to slow down the inspire in FF flight before releasing the stick, and even then it will come to a rapid stop when it senses neutral pitch input and goes into position hold. If you don't like that, try using P-ATTI mode (middle pos on the mode switch), but be prepared to deal with the fact that the Inspire will keep going unless you use opposite pitch input to slow down or stop the motion, and the Inspire will drift with the wind even once it stops because it is not trying to hold a GPS position.
Ed and Blade have asked for DJI to add stick expo on the pitch and roll stick as now is available on the yaw and throttle stick, but that has not been made available in a new app (it's not firmware related but app related to the controller). That might dampen the area around center stick and make it possible to get a smoother stop in P-GPS mode, bit it will still require a deliberate effort on your part to slow down the Inspire with controlled release toward center stick to tell the Inspire to slow down the rate of change in position (decrease forward velocity). If you have a rapid forward speed and let the stick snap to center it will react aggressively to hold that position by engaging ESC active braking of the motors. BTW, the same holds true for rapid side-to-side movement in roll mode. Again, P-ATTI will prevent that, but at the expense of losing the ability to hold a GPS position. Many videographers will tell you that they prefer P-ATTI mode when filming to get smoother craft movements, but it will require a bit more attention to dealing with craft momentum when flying, especially in windy conditions.
