Akainu was afraid samurai might have CoC
Really the admirals can't use their powers against a conqueror. Kizaru used a lightsword against Rayleigh which is to say a construct of his devil fruit, perhaps you could say in the same way Law cant use his spatial room abilities on Kaido or BM, but he can use countershock and Gamma Knife, which is to say is constructs of his df, but his actual spatial abilities dont work.
idk your thoughts
@Tejas on Kizaru vs Rayleigh, CoC, Ladmirals vs CoC users etc