Change Player falling vector to another than -Y

Hello Guys.

I've been trying to make a procedure that changes the "Gravity" of a player to the director vector that it is looking at, (something like Gravity API or Gravity changer), since those mods are not in forge. 

For the moment, i would like  to make a procedure that when pressing a keybind, the vector keeps non stop activating. My problem is that i've tried evertthing and it does not seem to be repeateable. 

Is there something i'm missing? Another way of "changing" gravity? A Way to keep overwritting the velocity vector? 

I've been stuck for a while and i would love to get some help.

(I'm using MCreator 2023.3 and the minecraft version is 1.19.2)

Thanks to everyone!