What's the best way to push a player forward

Hey Im working on a dashing data-pack for Minecraft Java 1.21.6 -- I need advice: in pure data-pack vanilla, what's the best way to push a player forward (apply a real velocity impulse, not teleport or speed potion) and the most stable trigger for an always-available dash ?
i want from the dash to always be available so it should not be tied to an item or armor enchantment , and the vanilla movement should stay normal. so dont tie the trigger to a movement ( if possible )
what i want to do is give a player a key (set of actions) that triggers the dash. its best if i do it with a mod so i can add a costume keybind but i dont know how to code with java so i want to start with a data-pack, 
if u have any advice for me i would really appreciate it