Replacing Rye/Pumpernickel Flour

So, I want to play with making a levain, which I’ve never done before, and I’m drawn to this recipe: https://www.kingarthurbaking.com/recipes/pain-au-levain-recipe mostly because I have used other King Arthur recipes with a lot of success. The thing is, it calls for pumpernickel flour and my spouse isn’t a fan. So can I just replace it with the same amount of… Whole wheat flour? Or just white all purpose flour? Or does that not really work and I need to find a new recipe?

Thanks!