is jujutsu kaisen episode 50 filler?

Yuji's group meets Tengen, who explains Kenjaku's endgame: merge Tengen with every non-sorcerer in Japan using stolen Idle Transfiguration, forcing a mass evolution of humanity. The Culling Game is the mechanism — its battles generate the energy needed for the merger.

The mission becomes clear: enter the game, accumulate points, add rules that allow escape, and find a way to break the Prison Realm holding Gojo.