Bus controllers + etc shrink in size too with each node progression. In fact, you can fit a 384 bit bus in less die space as the 256 bit bus on the Pro.
So my new conclusion is that non-cpu / gpu on the next gen console should only be around ~80mm2 if they don't add extra bus controllers, caches, dark silicon. In a
350mm2
die there should be 270mm2 to use, assuming cpu and Rops take around 100mm2, there is ~170mm2 remaining, which should fit 64 Vega 7 sized CUs with 30mm2 to spare.
New estimates for me is that >330mm2 SOC should be big enough to accommodate 8 core Zen2, 64CUs (4 disabled), 64 Rops.