Affirmative Action at the graduate level may or may not be a tip factor- but it absolutely will not get you in to a program for which you are not qualified in every other way. And if there is a tip, it will be a VERY modest one. So I would not worry about this at all.
If it were me- I’d be focused on the GRE prep…40th percentile with a B average in undergrad does not spell PhD.