Very common it seems for songs to change keys into a higher one but I dont think I’ve really ever heard something doing a descending modulation or key change…
closest I can think of is Strawberry Fields by The Beatles but my understanding is that is Varispeed or something, not really sure what the heck is happening in that song other then its gradually flattening but not sure what that even is
“Wandering Boy” by Randy Newman does something like what you’re describing.