We see Katakuri being pushed around, yes. But once again, nothing compared to what Boundman did - it sent him flying through the constructs after cleanly breaking his guard. And again, this is the second Snakeman attack - Katakuri showed the ability to adapt, keep up, block and dodge with Snakeman later on. Besides would you argue that this Jet Culverin is stronger than the King Cobra because that didn't push Katakuri like this?
Just because it sent Katakuri through a pillar? I don't buy it. It sure is faster and hence stronger than regular Jet Culverins though, I'll give you that.
Even going by your reasoning, it reached that level of power because Katakuri was dodging it forcing Luffy to stretch more and therefore accelerate more, thereby increasing it's power. On characters who won't be able to react or see it, the first blow or the second blow itself lands.
He danced around Black Mamba right after blocking it. The excuse that he had no way to dodge does not sell here, since he quite literally dodged a barrage of Black Mamba before landing his kick on Luffy.
Even in that CQC instance, Katakuri didn't force Snakeman into CQC, Luffy forced Katakuri into it.
The point is Katakuri was shown to never be able to stop Boundman physically but to be able to handle Snakeman physically.