How to manipulate a vector and how to get a trajectory like X are two completely different questions.
If using LaunchCharacter() for this, then you can set a initial velocity, after that gravity, friction and breaking decel will do the ‘falloff’ and you would need to tweak them (along with the initial launch vector) to get the desired trajectory.
If you want absolute precision with the trajectory taken then you probably don’t want LaunchCharacter(), and could maybe look into root motion sources.