the.com/gordian knot

means An extremely complicated problem that seems impossible to solve by ordinary, careful means — one that may only yield to a bold, decisive stroke instead.

from From the legend of Gordium: an oxcart was tied to a post with an impossibly intricate knot, and an oracle declared that whoever undid it would rule Asia. Many tried and failed by picking at it. Alexander the Great, the story goes, simply drew his sword and sliced it in half — solving the puzzle by force rather than finesse. Whether he actually cheated or truly untied it is disputed even in ancient sources, but the phrase stuck as shorthand for cutting through complexity rather than untangling it.