Counterattack System appeared when I'm already At The Mahayana Realm

My name is Jiang Li, and upon traversing to this realm, I found no golden opportunities waiting for me. Through sheer effort, I cultivated my way up to the Great Completion Stage. Now, suddenly, a system appears, claiming it can help me turn the tables and transform me from a minor Qi Cultivation phase practitioner into the foremost figure in the cultivation world. Dear system, you're a bit late to the party. I, Jiang Li, already stand as the Emperor of our era, revered across the nine provinces. I am already the number one in the Cultivation World. — Description from novelcodex.org