The title said "the most powerful rocket every built", which is hardly the case - SpaceX Starship has 12 mN sea-level thrust compared to just over 7.5 mN for SLS core, and Starship had already flew (some)! The difference in power is even more pronounced when you consider the full configuration (w/ 2 boosters for SLS and super-heavy for Starship, neither has a reliable launch date) at just over 35 mN for SLS vs a whopping 65 mN for SpaceX.
Reading the subtitle, it's clear that he meant "that NASA has ever built". Ahhh. Thanks for the clickbait.