Yes but that’s G4, when Luffy entered G5 his actual strongest form, he was never in any physical danger from Kizaru.
the only saving grace got Kizaru is their actual fight before Vega died was short but that’s more hopium
G5 is extremely extremely taxing for Luffy, it is the mode that is supposed to give him the edge against top tiers. Which is why it has this drawback. Luffy was already established a top tier before G5 was a thing.
In its entire run the best he could muster was landing a single attack on Kizaru which he almost immediately got up from to help an immobile Luffy get back on his feet. Essentially Kizaru was able to stalemate what is supposed to be Luffy's hyper overdrive mode which only lasts a few minutes tops,
after Luffy could not keep up with Kizaru in his other forms. That is not a good look for Luffy in any shape or form.
Ignoring all context and dumbing it down to 5 Gorosei and an Admiral were in that arc, ofcourse it sounds good for him. When you actually look at what was going on, he looked pretty bad. Especially against Kizaru in particular.
In the best case for Luffy, we just chalk it up to no serious fights on Egghead, just a bunch of senseless running around. Worst case for him, he deadass looks like he can't beat any top tier.