I don't know how much transistors the PS5 has but one thing I know, we can guess the size of the GPU portion of the PS5.
This site gives us the size of the ps4 GPU.
https://www.extremetech.com/extreme...u-reveals-the-consoles-real-cpu-and-gpu-specs
Which is 88 mm sq.
Now according to Mark Cerny, the size of each CU in the PS5 GPU is roughly 62% larger than a PS4 CU. Thus, there is the equivalent of 58 PS4 CUs in the PS5.
Going by this information.
The size of a PS4 CU is: 88 mm sq. divided by 20 CUs = 4.4 mm sq.
The size of the GPU portion of the PS5: 4.4 mm sq. multiply by 58 CUs = 255.2 mm sq.
But this 255.2 mm sq. doesn't include the disable CUs which is probably 4 CUs.
So, 40 PS5 CUs + (40×(62%)) = 64.8 or 65 PS4 CUs, which = 286 mm sq.
This 286 mm sq. is only the GPU. It doesn't include the CPU or I/O.
Like Mark Cerny said, "It is a fairly sizable GPU."
This is just my speculation btw.