I've always said the GOAT thing goes back to Michael Jordan. I think it also tracks to the internet age. Not only could sports pundits debate sports greatness, we all could, on the internet. I'm not sure what a "transcendent" GOAT means, or your recent "stylistic" GOAT, for Roger. (Which, sadly, never caught on.)
It's worth remembering that, while Roger is done, Rafa is not. Everyone keeps trying to call this some version of a closed question, including a couple of years ago, when some folks were happy to decide it was a done deal, with Rafa ending with the fewest Majors. Oops.
For what it's worth, when Rafa got to 21 and 22, ahead of Roger and Novak, I don't think most Rafa fans around here screamed out "GOAT," though the tennis pundits liked to do it. This is a complicated discussion. And
@El Dude has quoted me correctly to say that I don't think you'll ever separate the 3 of the, effectively.