You may just need to change your play style i managed to get it done with my 16.5k attack power alt account.

Team was heavy on the defensive,
soul was andromeda (only lvl 10)
amaterasu lvl.50,
amon lvl.40,
shiva lvl.40,
brynhilda lvl.40
subs nike lvl.30 cybele lvl.47.

I lost andromeda at around 60% of garuda's health which made me start losing kamihime prettty quick but pulled it off with 3 still left standing.