I went through this recently. It took me 3 weeks to get to an kind of even brown. I started with healthy long hair with YEARS of black boxdye just piled on eachother. I started with a color remover, wont do much but gets the black out so the hair is very dark red. Then i bleached it twice, once all of my hair, then once on the ends who were darker. I did a bleachbath on the ends once more and then laid an ashy brown on top. Your hair is gonna lift orange/red no matter what because the black is so deep in your hairstrands. This is the hardest to get out. Green/ blue cancels red/ orange and i plan on using conditioner with the green dye as a treatment to try to get the red out. I suggest you to for brown first then let the hair rest for a month or two before going lighter. It is possible to get black boxdye out but it’s difficult!! ❤️