the.com/house of cards

means A plan, organization, or system that looks stable but is actually so fragile that one small problem can make the whole thing collapse.

from From the literal child's game of stacking playing cards into a pyramid-like structure — cards are flat, slick, and have zero structural strength, so the taller the stack, the more inevitable its collapse. The phrase has been used figuratively since at least the 1600s for anything precarious built on a weak foundation, long before it became a go-to metaphor for shaky finances, conspiracies, and doomed Netflix presidencies alike.