In the version we saw on screen, we saw the iconic group shot of the Avengers from that film which was our establishing shot to tell the audience where in the battle we’re coming in.
The editors behind Avengers: Endgame have revealed that, among the changes that the movie saw in the editing bay, was the way that the heroes entered the battle of New York from the original Avengers film.
It seems that initially the time travelers joined the story a little bit later in the battle.