I did not know that that particular scene was the deleted footage from Endgame. Still, it was so fuzzy in the episode, that they could easily cook up a copy of the set similar to it, and reshoot the scene from a different angle. I don't think that would be hard at all.
I didn't say it was hard. I said I don't think they'd do it. The set work on WandaVision has been pretty controlled (so I don't know that they'd spend the $$ for a single sequence), and I don't think they are interested in telling us all the details about everything that happened before the show began.