Patchy white/lilac/blonde... What to do now?

Ok so history: 4/5inches of level 5 virgin hair, 2/3 inches of semi perm level 5 brown (1 application) 4/5 inches of pre lightened hair on top of a once semi perm level 2 colour (again 1 application)

I've done 1 round of blondme bleach with 20 vol developer all over with blue additive and olaplex and a 2nd round almost all over but avoiding 1+1/2 inches of roots. I was expecting to have to go back and maybe spot bleach a bit but it seems to be really patchy all over with some parts really sucking up the violet and some parts remaining a warmer beigey blonde.

I've tried some strong violet shampoo which again just takes in certain parts and not the beige bits. I'm not sure if the beige bits would lift any further if I did another bleach on those parts later or if they just won't shift now. My hair is very dense and super thick and mildly coarse but the ends are a bit dry now... although I don't mind losing some hair to snapping as I have so much of the damn stuff.

I'm not sure where to go from here as it just looks so patchy. Ideally I was shooting for platinum or pastel lilac or even a silvery colour but I'm just not sure the hair past the first 5 inches will get there. Ideally as I know i can get my virgin hair to white now that's where I'd like to eventually be so is there a colour I could go now that will make my colour uniform but is easy to revert back from to go to white in the future when I've grown the beige lengths out? I don't mind being blonde but prefer cool tones.