hair dye not sticking to roots

basically what the caption says. i have been dyeing my hair pink at home for the past 2 months and i love it but i just cant seem to get the dye to stick to my roots at all.

im naturally a level 8ish dirty blonde and before the pink i was bleaching my hair platinum blonde. ive continued to bleach my roots for the pink.

i am using the bleach london rose and leave it on for roughly 2 hours each time. when i wash it off the top like 3 inches of my hair barely takes. its always like a peachy pale pink colour. it holds better when ive just bleached but its not a crazy difference.

and i mean like i get a wash out of it, 2 if im lucky before its back to blonde, whereas my mid to ends will hold the pink for roughly 10 washes. i wash my hair in lukewarm or cold water, never ever hot.

is there anything i can do, for example a pretreatment, to help it stick to my roots or is it maybe just a bad dye?

i’ve dyed my hair pink before but i only had it in for about 2 weeks before i colour stripped/bleached it out so i dont have anything to compare it too.

and if it is a bad dye does anyone have any dye recommendations? im in the uk and looking for a light pink, king kylie pink.

thank you!