By default, the maximum speed in the Space Engineers game is only about a hundred meters per second..
In order to change the maximum speed in the game, it is enough to change the values of a couple of variables in the game files.
Open the file with notepad …\ SpaceEngineers \ Content \ Data \ Environment.sbc, find values SmallShipMaxSpeed and LargeShipMaxSpeed and change them as you like.
Remember that parachutes are designed for standard maximum speed, parachute loads will break; also, there may be changes with some features of the operation of mods related to mass, speed or strength.