Well the thing is Kizaru is potentially hiding his awakening. He's already comfortably above Luffy without it.
Luffy is fodder to Rayleigh
Rayleigh was also holding back on everything, advanced techniques and Haki ranged attacks and special form of his arsenal.
At Old Rayleigh showed Kizarus LS Kick and Yasakani no Magatama are worthless against suppressed Old and Rusty Rayleigh.
Kizaru would need awakening and then some to stand a chance against Old Rayleigh.
Prime Rayleigh just grabs him by balls and beats the fuck out of him.
Sakazuki and other admirals are even easier.