I somehow effed up, please help! (HOT ROOTS)

Hello!

So I've read the bleach bathing thread over a couple of times and am still a bit stuck at what to do regarding my hair.

I'm in the process of attempting to go from box dye dark brown/ black to auburn. I decided to do this I was going to try to use a colour remover, bleach bath it until it got to a light enough brown to apply a copper semi over it (using my already by then I was assuming reddish brown base for the auburn). I bleach bathed once using vol 20 as my developer which didn't do much, applied JoBaz which further did barely anything except stank for several days, before applying a second bleach bath a week later.

Second bleach bath in, things have started to go wrong. I assume my mid lengths and ends are pretty stained from the crappy dark dye, as it's barely budging, particularly on my mid sections. Unfortunately the last bleach bath worked... but on my roots only, dying them a light orange, almost brassy gold on some parts despite doing them last and wrapping up my hair (virgin 2 inch-ish naturally med brown roots).

I have quite long hair (almost waist length), and by the time I have wrapped it all up after applying the bleach bath, I'm not sure the ends are getting warm enough from the heat on my head to develop. Particularly because I've got coconut oil on, too?

So the point is, I now have orange roots with dark brown mids and ends, in which the colour change is very abrupt and obvious. I don't want to have to go back darker, but I'm reaaaally stuck as to where to go from here as I still want to go auburn. Any suggestions? TIA.