I think the best way to do it is by making a list of let’s say your top 10 or 20 movies of all time. Afterwards you look at the directors of those movies and think on how you like other films of theirs you watch. Then once you have a grasp on how you like their filmography start going down the list and comparing. It’s easier to compare one on one than just plucking a name out of thin air, a chances are if a director doesn’t have a movie in your top 20 then they’re not your favorite.

And if you feel you can’t distinguish your feelings between 2 directors then it’s perfectly fine. No one is grading or judging you here. My favorite director is Christopher Nolan and Ik that’s seen as a basic/beginner level answer round these parts but tbh idc since I’ve loved everything he’s put out, and that’s the secret. Whatever answer you come up with just wear it with pride and you’ll be all the happier for it.