How to lower mouse sensitivity lower than 0?

I play on 800dpi and 0 sens is still way too fast, I know for a fact you used to be able to change this in the config files, but it seems like that has changed, or at least I cannot find it myself, or anything online. Please tell me theres still a way to change my sens lower than 0, I really don't want to change my dpi every time I launch the game, also changing dpi makes it hard to navigate the menus, its just such a shitty workaround.