It was when the music was them, which was in conjunction when it being made for the fans. "I NEED U" encapsulates BTS at their purest.
It all started to go downhill with "Blood Sweat Tears," when they started making music for a cause, to play up to the woke mob with its identity politics with the pandering element of ambiguity in both the music and its accompanied music video.
"I NEED U" was their peak because it was them.