If you use any type of standard controller E,G; Xbox 360 or PS4 or A generic xinput controller you can use Steam's big picture mode to gain access to a fully in built Controller config utility.
Originally designed for use with the steam controller it's been made available for full use with PS4 controllers and most functionality with other PC compatible controllers a little while back.
You can find a full guide here:
https://www.howtogeek.com/234427/how-to-remap-buttons-on-your-steam-controller
It will let you map the thumbstick to a D-Pad input or let you tweak the dead zones of what is considered where on the thumb stick.
Or even to Complex Macros for anyone so inclined.
Originally designed for use with the steam controller it's been made available for full use with PS4 controllers and most functionality with other PC compatible controllers a little while back.
You can find a full guide here:
https://www.howtogeek.com/234427/how-to-remap-buttons-on-your-steam-controller
It will let you map the thumbstick to a D-Pad input or let you tweak the dead zones of what is considered where on the thumb stick.
Or even to Complex Macros for anyone so inclined.