Others have similar speculations, one example: https://medium.com/the-left-is-right/biden-trolled-trump-one-last-time-4c71895434cc
As a USA citizen watching the Dems mostly shoot themselves in both feet for multiple election cycles now, I can't quite imagine that this was all so carefully orchestrated. I do hope that at least some key points were, like Biden waiting to opt out until the RNC was well over. As Napoleon allegedly said, "never interrupt your enemy when he is making a mistake."
At the least, it's wonderful to see the kerfuffle this has created among the MAGAts. So far they've got nothing but empty invective (though that's mostly all they've ever had). Also good to see the apparent energizing & engagement of various demographics that were significantly disaffected by Biden.