How can you identify an Airbus and or Boeing from the inside based on features of the interior?
You can't, unfortunately, airlines (of same type) choose different seat manufacturers, etc.

It's like asking how to identify a building's architecture from one room.

We can discuss wing shapes, or a tail camera's feed on the IFE if there's one, but what if you're stuck on the middle seat of the middle column on a wide-body without a tail camera and no wing view?