Concurrency and Selenium - Multiprocessing vs Multithreading
Web driver is just a driver, a driver cannot drive a car without a car.
For example when you use ChromeDriver to communicate with browser, you are launching Chrome. And ChromeDriver itself does no calculation but Chrome does.
So to clarify, webdriver is a tool to manipulate browser but itself is not a browser.
Based on this, definitely you should choose thread pool instead of process pool as it is surely an I/O bound problem in your python script.