Washing hair before or after dying???

To make a long story short, im trying to fix the ends of my hair and make it black again (keeping to solid black or ghost roots i can achieve without bleach to keep damage minimal, despite coloring, i havent used Splat in YEARS and i never will again lol) im thinking of using a peminant dye because im not consindering lightening my ends for a long while. i just wanna dye from about 1 1/2 - 2 inches from my scalp to the ends, i havent washed my hair in 2 days and put coconut oil in it last night (just enough to help my hair hydrate) and i keep recieving conflicting info as tk whether i should dye my hair or not.

If theres excess detail i apologize i just wanna make sure i lay out my plan clearly so i can get proper advice. im not going to be putting anything else in, litterally just redoing my black cause its faded to the point its light brown. any and all advice would be very much appriciated!!! <3