My Gatekeeper System in the Prehistoric Era

For billions of years, I've been a vast spiritual river on Jinao Island, cultivated endlessly, yet I'm still trapped in liquid form! Worse, my casual bragging has convinced powerful monster spirits I'm some ancient, peerless expert, and now they beg for teachings I don't possess. My grand charade is about to collapse. Suddenly, a Heavenly Saint, Master Tongtian, descends to claim my island! Panicked, I immediately prostrate myself, begging discipleship. Ding! Gatekeeper System Online! Guard the gate of Jinao Island, protect Jiejiao's destiny! Now, this 'river spirit' must screen every aspiring immortal, including future direct disciples and notorious troublemakers, all while the ominous shadow of the Conferred God Calamity looms. Can a fake expert with a sudden system save the most chaotic sect in the Three Realms?