I might have fallen asleep but no longer than 20 minutes.
Monica Rambeau suddenly reforms inside Parkside Hospital after being gone for 5 years.
While not 100% certain of this location, numerous sites reported that filming for WandaVision took place at the Southern Regional Medical Center, months prior to the airing of the show. Since no other reported location seemed to come close, this seems like a likely candidate.
(WandaVision S01E04, 2021)