The aftermath of the Arrowverse's Crisis on Infinite Earths turns Brandon Routh's Superman back into the movie version of the character from Superman Returns. In other words, Routh's character is no longer the Kingdom Come Superman. It was revealed early in "Crisis" that Routh's character actually is his Superman Returns character, which means that both Superman Returns and the four Superman movies starring Christopher Reeve are now Arrowverse canon.
The Batwoman episode of Crisis on Infinite Earths introduced viewers to Earth-96, the home of the Kingdom Come Superman, a version of the Man of Steel who had lost Lois Lane, Jimmy Olsen, and Perry White to an attack on the Daily Planet. It's discovered that Superman is one of seven Paragons destined to save the multiverse from the Anti-Monitor (LaMonica Garrett). Superman joins forces with the other Arrowverse heroes to stop him. At the end of part three, Superman is one of the only characters to survive the destruction of the Infinite Earths, but is killed when Lex Luthor (Jon Cryer) uses the Book of Destiny to take his place as a Paragon.
Following the final battle between Oliver Queen's Spectre (Stephen Amell) and the Anti-Monitor in the final chapter of "Crisis on Infinite Earths", the universe is reborn, and seven Earths are created, one of which being a remade Earth-96, a world that includes Routh's Superman. Superman is shown flying, and there's one noticeable difference from his last Arrowverse appearance: the black emblem of the Kingdom Come character is gone, having been replaced by the traditional yellow House of El emblem. The change symbolizes that the movie version of Superman has been fully restored.
As explained by Superman, he wore the black emblem because of the tragedies that had taken place in the past. He wanted to show that "hope cuts through", even in the "darkest of times". So it would seem that in the reborn universe, the events Superman related to the Arrowverse characters involving the deaths at the Daily Planet never happened, which amounts to a happy ending of sorts for the Big Blue Boy Scout. The deaths of Lois Lane and all the others have apparently been reversed.
Crisis on Infinite Earths took everything from Superman, but gave it all back to him in the end. Despite everything he lost, Superman never stopped being a symbol of hope. For fans of the classic Superman movies (and Superman Returns), this final glimpse at Routh's character flying through the sky provides a satisfying conclusion to a story that succeeded in staying true to the spirit of Superman, as well as the most iconic adaptation of the DC Comics, the Reeves version. Perhaps the biggest disappointment regarding the character is that this Superman won't be returning for his own Arrowverse series.