Give Nakamura a minute with Stockfish any two times of his choosing in each game, and he would have probably won the Candidates.
Heck, just give a good player a blunder alert that tells them after they have made a blunder that they have done so and it could make a big difference.
There were games in the Candidates where a player would make a blunder that would completely turn the game around if the opponent found the one move that exploited it, but the opponent didn't see it. The first player could have then saved themselves but had not yet realized they blundered so didn't. Then the other player realized what was going on and exploited the blunder.