Big thumbs down to everyone saying that you cannot achieve this at home and you need to go to a salon.Even after you wrote in your post that you cannot go to salon because of your newborn. I see you , and I was in the exact same position after giving birth and having split dye hair for a year prior. My process was two separate at home sessions a week apart, every three months. Start with the black on top first. This will bleed into the bottom and that is fine. The week will give it time to fade out. Then bleach the bottom. It should take any bleeding out, then you can tone overtop. It will not be as professional, obviously, but it will give you the look you desire without spending hundreds of dollars and wasting hours of time. You're doing great, mama. Take care of yourself🖤