We Interrupt This Program

The barely intelligible words at the beginning of the episode while Monica is coming back from the blip are pieces of dialogue from Captain Marvel (2019), where Monica was just a child. It's like her mind is recomposing itself by experiencing again every memory in Monica's life.

When Darcy asks for an "old TV...not a flat one" to watch the broadcast from within Westview, the one she gets is from the 1950s. Analog TV broadcasts in the US have not changed since they began, so any TV (including flat screens) made before about 2015 (when all analog TV broadcasts were switched off in the US) would work fine.

But, since this takes place during 2023, she's right to specify an "old one, not a flat one" . If she had just said an "old TV", she might have gotten one from 2018 which would not have worked. By specifying "not a flat one" she was much more likely to get what she needed.

Edited into Marvel Studios: Legends: The Scarlet Witch (2022)