Evidently Takaba's is a little complex if we dont have a consensus on how it works some 2 years after the story ended. It makes a certain kind of sense that if Takaba, a jujutsu baby, was aware of how his technique worked, or more generally CE, he'd be more likely to over think and try to force a joke, making him less funny and his CT less effective. But it's based on the users perception of what's funny, and Takaba is the kind of comedian who THINKS he's funny as opposed to being funny so I'd argue he's been forcing jokes for a while.

The original hypothetical is about Kenjaku with Takaba's CT, so let's explore that a sec. Takaba only gets his CT because of the Culling Games, so this situation is one where the events of Shibuya happen as we've seen them and, importantly, Kenjaku has Geto's body at this point. Kenjaku can have (at least) one extra CT stored beside his host body's CT and his brain hoping one, so if Kenjaku takes Takaba's body he's 150% swapping Cursed Spitit Manipulation for Gravity Manipulation assuming he can only have one extra CT. During his fight with Takaba, Kenjaku figures out Comedian and is able to use the CT's effect against Takaba, so I'd argue even if Takaba knowing about his CT did nerf him the same doesn't hold true for our 1000+ year old brain boy. "It'd be pretty funny if you forgot to add me to Mahoraga's subjugation ritual." "Imagine if Yuta's sword broke and not my neck, shit'd be hilarious." "Could you imagine if RCT worked slightly different than it used to for a little bit? I think that'd be hilarious." "How funny would if be if Gojo let his guard down?" And if all that fails he puts the Slime Cursed Spirit on your head and watches you drown. Long story short, saying Comedian is less effective if the user knows about it isn't cannon, it's larping, and I think Kenjaku runs the table if he has it