This guide will tell you how to fix FIX STICK DRIFT on Controller in FORTNITE.
In Fortnite, you have a dead zone slider that you can adjust. You have to press the options button, go to settings and then navigate to the controller option under Input. After that, scroll down until you get to the controller dead zone. It says to increase or decrease the area around the surrounding stick, setting this value too low may result in the character continuing to move even after removing your finger from the stick. Now inside the circle, you will find another blue circle and you can make it larger by using the slider on the left.
When will you apply pressure to your thumbstick, you will find a yellow circle inside that blue circle. You can set the threshold to the side and expand this to fill the entire circle.
Now you may see something on the screen like a yellow circle, it is the area where your thumbstick is still moving. You have to make this blue circle big enough, so the yellow circle fits inside of it.