Listening to all three in order I am left with one question/theory.

The “whisper voice” that is prominent on NTAE and AV (such as Dear World, The Idea Of You, The Lovers), the conflicting feelings/self talk/questioning, and the idea of being “asleep” alll seem to be gone on BW. In their place, we have a new voice (seen on God Break Down The Door and Over And Out) on BW. BW seems to leave behind all the questioning, ambiguity, and confusion of the first two acts.

I see two answers/theories for this. 1) The whisper voice was part of the sci-fi explanation/ending that was changed. 2) The Background World is the integration/destruction of the simulation. Bad Witch leaves us with something integrated and new. Gone is the questioning if everyone is asleep. The simulation has either been destroyed or integrated within the main character to the point where they no longer notice it. The real world equivalent of our acceptance of how social media and technology have changed/corrupted our view of the world. The new voice is this integrated/corrupted perspective.

With this, I think all three have to be played in order. The Background World destroys a part of the narrative and all of Bad Witch occurs after that destruction.