The machine, hands down.
These days the machine is so incomparably stronger than a player, that even if a player comes up with a better long-term strategy, they will still lose to inevitably missing tactics. Even if they don't outright drop material, they will overlook threats and walk into a situation where they need to concede positional advantage to not lose that material.
It's good to understand the role of Engines in human opening preparation. Players would play through various lines against a computer looking for a good position, and using the engine to spot and avoid tactical problems for themselves, while laying tactical problems for the opponent. Thus when they get to the board, if the line played out matches the studies of one player more than the other, they will instantly know which moves to play and the other is in danger of falling prey to the tactics uncovered by the machine.
This is why Fischer invented Random, to get away from excessive analysis. It is impossible for a player to memorize 960 opening schemes. Yet a computer is capable of memorizing, playing itself thousands of matches AFK. But even if you throw that opening book out (and with the new generation following Alpha Zero, this doesn't even make sense) and elite players win the strategy of the opening, yet machines will crush them in the execution.