To start as a stand-up comic, it's important to build confidence. Start by attending open mic nights and observing other comics. Also, keep writing and refining your jokes based on the audience's reaction.
Sakura can stand out by showing her medical ninjutsu skills. Since she has a natural aptitude for it, she could use it in creative ways during the exams. For example, she could heal her opponents during a fight to show mercy and strategic thinking, which is not a common approach in the Chunin Exams.
Sukuna does die in the manga. The way it happens is quite dramatic and ties in with many other elements of the story, adding depth and tension to the overall narrative.