Is there a button to adjust the speed of the ship, I mean, are there options such as 100%, 75%, 50%, 25% for the thrusters, if not, can you add them thus saving energy and reducing unwanted movements?
Thusters And Energy
There isn't. Most of the time there's no reason to either. You always want speed and AI adjusts based on distance. Only very light ships or badly designed ships suffer.
As is it's troublesome to even mod it: either with complicated logic or complicated buffing.