I think BTS's legendary performance is definitely 'Butter'.

I think BTS's "Butter" performance at the 2021 American Music Awards was the greatest legendary performance that captivated the eyes and ears of fans worldwide.

As soon as the performance began, the members appeared to an upbeat brass beat that immediately captivated the audience. The overall yellow-toned set and costumes perfectly complemented the song's fresh and gentle atmosphere. The sophisticated and energetic group choreography unfolding right from the intro of "Japchae" was truly beyond imagination. I consider it a perfect, legendary performance.