If I post without agenda or bias my opinion is:
Luffy was more invested in their fight than Kizaru was, that's a fact, even if both weren't serious, Kizaru was always on panel admitting to not want doing what he had to do.
I agree that Luffy was more invest because he was tasked to keep Kizaru occupied but he in no way seemed interested in destroying him like he was with Kaido and thats my point lol.
I bet if you had a Yonko feeding an Admiral you guys wouldn't shut up saying we were finished, Luffy was using Awakenening + ACoC, in fact Kizaru was the only character Luffy used ACoC on.
He used ACoC once, (twice if you think the greeting kick was ACoC)
That fight has many asterisks to be powerscalled, who knows if Kizaru had something up his sleeve, who knows how strong he truly is. The fact is that he helped Luffy which questions everything from the amount of effort he gave, the thread he wasn't but could be if he wanted, and so on so forth.
I agree both sides held back somewhat, I think ACoC is a huge power boost that Luffy barely used for example and Kizaru didnt really want to fight Luffy. I think Kizaru is the perfect matchup against Luffy because his speed works very well against someone on a timer, other Yonko dont have a timer for example so the fight would go differently if you understand what Im saying.
I appreciate your non biased answer, I think Kizaru does have awakening but imo its what would make fighting an all out Yonko who are peers of Admirals ( something I said for years) with ACoC. Luffy is just facing a really bad matchup in Kizaru and imo when it comes to fights between top tiers matchups matter a lot.