OK I replayed my game and think I get what you mean: Single tap input result in too much movement, takes too long to stop, and the reverse movement input doesn't mitigate the inertia but instead push you to the opposite direction.
Sorry my movement implementation is way too primal, like I only used a coefficient of below 1 to reduce the speed down to 0. Math is not my strongpoint, but I will learn to implement better physics in the future.