The Young Emperor's Journey to Immortality

There was once a conjecture that the human body is composed of countless extremely small and extremely large universes. This conjecture cannot be proven only because human technology is not developed enough today. Now, a young man named Yang Yan inadvertently develops the infinite universe in his body and reaches the pinnacle of immortality in one fell swoop. He happens to be on earth and enters the age of immortality. How will he decide his own path?