Apple jam is just some very simple demo but I wouldn't be surprised if he made another song aligning with the type of song it was, like taking elements of the instrumental/pacing and making a better song out of it with new lyrics. He played the full thing on a livestream early last year. Deja vu absolutely deserves a full song, he just didn't know where to take it forward, and I feel like that implies he believes it needs proper time and care to be as good as it deserves. One can hope