Marvel: I Became Vision

Li Nian, a die-hard Marvel fan, is watching Avengers: Endgame at home for the fourth time when he unexpectedly finds himself transported to the events of Avengers: Age of Ultron. To his astonishment, he has become Vision-the poor sap who died twice. Gazing at the ruins of Sokovia, he recalls the horrifying future in which Thanos tears the stone from his forehead, Wanda sobs in grief, and Quicksilver meets a tragic end...

A red-and-green figure hovers high in the air, looking down upon a battered and bedraggled Thanos.

"This time, you're facing Infinite Vision."

P.S. The protagonist will travel to other American comic-book universes.