the.com/point of no return

means The stage in a journey or undertaking past which reversing course is impossible or more costly than simply continuing.

from Originally aviation jargon: the point in a flight when a plane no longer has enough fuel to turn back to its origin and must continue to its destination. The phrase lifted off into general use in the mid-20th century, especially popularized by the 1958 novel/film 'The Point of No Return,' and has since fueled countless metaphors for commitment, risk, and no-going-back decisions far from any runway.