What is a similarity between the ways that willem de kooning and jackson pollock approached the process of painting?

The answer is that they both emphasized the process of painting more than the end result itself

They focused on various different ways to create art itself which included things like the concept of "action painting" in which the work of art would be created through very active movement and not just by sitting and painting. Pollock even got a nickname "jack the dripper" because of how he would for example stand above the painting and drip color on it in different patterns instead of using a brush.