During Order 66, pretty much every Jedi went out like a punk to handfuls of Clone Troopers, even the masters (One by a single starfighter, one by half a dozen clones on a bridge, one by a couple clones in a forest, one by two clones on speeder bikes). In the context of the movie, it is made to seem like Anakin and the rest of the Jedi in the temple were just overrun by literally hundreds of Clone Troops, in wave after wave. Only by ANH did Ben reveal that another Jedi participated in Anakin’s death. Arguably under this idea, Anakin lasted longer than the rest of the Jedi while sustaining attacks from all sides.

But I agree that changing things through opening crawls is inelegant, yet there’s really no other way to do it unless one was to fabricate a new scene.