Dying my hair

Okay so I haven’t dyed my hair in a year or so since I’ve been trying to grow it out

I want to make my highlights a bit lighter and more on the top than just on the bottom so I picked out an 8NN which is an intense natural blonde but since I’m just trying to go a few level lighter I’m thinking of using either a 30 Vol or a 20 vol

Which developer would be better for me to use

This is my hair (excuse the dirty mirror its my sons bathroom)

This is the color I bought