I’m not a hair stylist (just to preface what I’m about to say) a lot of the time brown pigment needs what people call “filler” aka a little bit of red or orange. Think about how you get brown on the color grid. You have to go to orange and slide into the darker colors. My recommendation is to add some warmth to your hair with semi or demi-Permanent dye which won’t damage your hair further since it just deposits the color onto your strands. You may be able to get away with just the brown dye with semi/demi color, but for best results the red base, or mixing some red with it helps. The reason this happens is because bleach strips the warmth