This isn't necessarily for GTA, but I'd just like to throw this out there and (hopefully) get some help on this.
So I have two PS4 controllers. One of them works perfectly fine, but the other one... not so much, When I push up or down on the left stick on it, it doesn't move at full speed. It only goes at about 30-40% normal, and while GTA doesn't have to worry too much because ANY input in that direction works the same as 100%, games like CoD and (much more importantly) Fallout are nigh unplayable, because you lack the full movement speed directly forwards. So unless I want to strafe to the side whenever I move, I have to do something equal to the slow walk from carrying too much crap. And it's annoying as hell.
Just asking, any home fixing suggestions? Hoping to do this without tearing the thing apart, or sending it away for repairs.
I'd suggest try to clean out the area around the left stick using a compressed air can. A lot of dust and other stuff can build up around the sticks after using them for a while. You can remove the screws on the back of the controller and and clean it internally. There's plenty of videos on youtube that show you how to take apart the controller if you need help with it. Hopefully that fixes your issue.