Lmao your beef is with Oda then, take it up with him on why he made Kizaru so strong and so versatile, that he can use someone elses primary fighting style against them. Reminds me of Vergo deciding to kick only against Sanji. Some people are just that versatile.
Also you're looking at it wrong, Kizaru wasn't keeping up with Rayleigh, Rayleigh was keeping up with Kizaru. Kizaru is the fastest man in the manga, you could almost see how fast he was (could literally see light emitting from his swinging speed), it was taking a toll on Rayleigh keeping up with him.
Kizaru used an imitation blade to shield himself against a top tier swordsman, the right choice in a CQC situation against Rayleigh, swordmanship could play a role but it's almost negligible compared to his speed and strength. All marines train in swordmanship, yes including Coby, doesn't make them a swordsman, Kizaru is simply that fast and powerful.
Your argument holds no merit.