Sima Yi, named Zhong Da, refused to work for Cao Cao at first because he didn't like his background. However, after Cao Cao became prime minister, he was forced to grant an official position. Sima Yi, with extraordinary wisdom, made suggestions for Cao Cao many times, gradually won the trust of Cao Cao, and assisted Cao Pi after he ascended the throne. Sima Yi showed great wisdom in Zhuge Liang's Northern Expedition and made a surprise attack on Zhuge Liang. In the end, the Northern Expedition never progressed, and Zhuge Liang died on the way to the Northern Expedition. It can be seen that Sima Yi is far-sighted.
In my opinion, I think Zhuge Liang is more powerful. Although Sima Yi had the last laugh, Zhuge Liang's contribution to Shu was far greater than Sima Yi's contribution to Wei. Many events show Zhuge Liang's extraordinary wisdom, such as "borrowing an arrow from a straw boat", "borrowing the east wind", "Battle of Red Cliffs", "arguing Confucianism" and "empty city plan", all of which show Zhuge Liang's powerful ability, great strategy and outstanding intelligence.