What setting takes the most skill to win?

You know. Is it no cards with freestyle? Is it escalating sequential with chained? Or any of the many possibilities? Is it harder to win 1vs1 with no cards than a 2vs2 with escalating?
Many possibilities, share your thoughts. What do you think is the setting that takes the most skill? (Or the least.)
Many possibilities, share your thoughts. What do you think is the setting that takes the most skill? (Or the least.)