Here's another good interview with Jay Wadley--this one via Spin--speaking about his score for I'm Thinking of Ending Things. Spoilery, so beware.

What was that initial meeting like?
It was a great initial conversation that was largely about conceptual elements. At this point, we weren’t sure how much actual post-scoring there was going to be, if any at all. There was definitely going to be this jingle. There was going to be the pastiche rom-com. They were licensing the Oklahoma! tunes. It wouldn’t have worked to use the ballet from Oklahoma! because we would have had to rearrange all the themes and redo the whole thing. So we decided to do it all  [as an] original score, the concept being that it needs to be a part of this fabric, and what does the memory of music sound like? Or the misremembering of music?

[We were] playing with some of those concepts in the ballet by making it a piece that sounds like it could be from Debussy, or from Ravel or Stravinsky. But definitely feels like it could be something Jake would have heard at some point in his life, so that when he’s imagining this entire romantic ballet sequence that’s sort of representing this life unlived, what music is he imagining accompanying this thing? It’s all fabricated in his head and part of his imagination. (Source)

This video's included on Spin's site, too: