A rather shallow analysis beyond the die size estimate itself. We do know the size of multiple 7 nm AMD GPUs, APUs and CPUs, for instance, not to mention the size of specific components inside the current consoles' APUs.
It would seem to me, though, that considering the rather large size of the RDNA machinery, not to mention Zen and whatever RT solution AMD has cooked up, it seems troublesome to imagine more than 48 or 52 CUs fitting in there.
I'm thinking more of the Hovis method and vapor chambers instead of a very wide 56 - 64 CU solution as some people have been speculating. And if you think 12 TF is indeed a thing, 48 CUs at ~ 1950 MHz with 4 more disabled would still seem commercially feasible considering even now many custom GPU solutions are required to hit boost clocks around 2000 MHz.