TPU says 750mm2 compared to 330mm2 for Vega20. Should wait for some actual measurements, I don't know where they got those numbers.Vega20 still had rasterization hardware in it. It was a full blown GPU.
CDNA cards aren't video cards. They don't have the ability to output video. So yes, it will be larger than Vega20, but unlikely to be double as it had lots of stuff removed that Vega20 had.