/cgl/ - Cosplay & EGL

I need some experience advice here.
I (badly) bleached my orangey brown with asian black-brown roots to an uneven yellow, put a purple dye over it, then dyed it dark brown. I cut off like 8 inches when I first dyed it back. Before that, I had had it done professionally. I've had to redye it dark brown several times now because it fades so much.
This color is really making me sad, but I just can't really afford to go to the salon every other month anymore, and I don't trust myself or my friends with bleach anymore. I'm considering getting one of those box dyes that are intended for lightening dark hair, but I have about 5 inches of unbleached and 8 inches of bleached. I only want it to be like medium brown, I've found that lighter hair doesn't suit me. Will it dye terribly and unevenly? I can go to a salon like once or twice but if I could find something less expensive and low maintenance, that would be great.
Pic related is me. The bottom left is bad quality, but it's a gold yellowy brown. The bottom right is a little over exposed, it's still darkish but more red toned.

tl;dr can I use a lightening box dye on half bleached half unbleached hair that's all been dyed over dark brown and then faded or will it be uneven and shit