Never mind this chapter. The first thing he did when he saw Bonney again was kick her off the labophase, directly into a deadly laser barrier and the huge drop afterward.
The meme idea of lazy stoner Kizaru and now conflicted Kizaru have made an imaginary picture of him that has no bearing to reality.
He’s not a stoner, he speaks slowly and is laidback in style as a play on him actually being extremely fast.
Kizaru’s actual actions are of someone who follows orders, is quick to go into battle and is loyal to the Celestial Dragons.
Saobody- he volunteers to go when Charloss is hit. He tries his best to get the Strawhats, and is hugely frustrated when he fails, capturing 500 pirates in anger because of it.
Marineford- perfectly eager to fight
Before Wano- volunteers to go fight the Yonko
Egghead- beat up Sentomaru when he didn’t have to because he respected him, has attacked Bonney and Vegapunk, put them both in danger. And in general has zero qualms about fighting the Strawhats, because why would he?
He’s clearly respectful and subordinate to Saturn without being servile. He gets him his tea, he apologises for letting him down.
Kizaru has fought to the exact same level that he’s always fought. There’s nothing inconsistent about his feats from Saobody to Egghead. He is a top tier, but he is nothing overly special among top tiers, other than his speed.
And while Kizaru doesn’t like what he’s being told to do on Egghead, he’s still had absolutely no trouble doing it. He is picking duty over friendship, there is zero signs he’s holding back because of it, and he actually went out his way to fight Sentomaru precisely because both are putting their convictions on the line.
He may, at his very final moment choose friendship over duty, but he is far, far removed from that so far.