michel wrote: "I don't think they ever gave a direct advantage for the last challenge."

Actually two seasons back to back (S25 Philippines and S26 Caramoan) had a Reward Challenge where the Reward was an Advantage for the Final Immunity Challenge.

S25E014 Philippines Finale Reward Challenge

Reward Challenge: The castaways would run an obstacle course of a balance beam, over a wooden pyramid, a bamboo thicket, a second balance beam, and up a wood ramp to collect three puzzle bags. The castaways would then use the puzzle pieces to assemble a puzzle. The first castaway to finish the puzzle would win an advantage at the Final Immunity Challenge.

• Malcolm WON the Reward Advantage that stated he would be given a mulligan in the challenge. If he were to drop the ball, he would be allowed to replace the ball and resume the challenge.
  
• Malcolm LOST the Final Immunity Challenge

S26E014 Caramoan Finale Reward Challenge

Reward Challenge: The castaways would use one hand to hold on to a rope to steady a balancing board. With the other hand, they would build a house of cards with wooden tiles on one end of the balancing board. The first castaway to build a tall enough house of cards to reach the finish mark would win an advantage at the Final Immunity Challenge.

• Cochran WON the Reward Advantage: His puzzle piece bags would not be tied to a post.
  
• Cochran WON the Final Immunity Challenge