Walk speed by direction

I want to be able to have something where if I face a certain direction of a map, my walk speed will drop or rise.
so pretend I’m facing south, my speed will drop by 10, and facing north it’ll be normal.
East or west it’s semi, where you can walk fine but you’re being nudged to the north

i’m pretty sure you can use the dot product for this. the dot product gets the similarity between 2 vectors. so pretend the maps look vector is north. and the character is facing north, the dot product would return 1, because they are facing relatively the same direction. the dot product would return -1 if the player is facing the opposite direction.
Vector3 Dot Product: Calculating NPC Field of View (Roblox Studio) - YouTube

will this work on local player instead of NPC? because then maybe I can put the POV set to the players head, then put 4 points on the map to represent N,S,E, and W