As you can see above, semi-custom is already AMD's biggest income, they have no chance at beating NVidia head to head in the discrete GPU area, so what I suggest is leaving or limiting PC GPU manufacture to leave NVidia charge whatever they want, even drive up prices by charging more for their own fewer GPU's increasing margins.
Then put their full force behind console GPU production, creating more efficient economies of scale and pushing more gamers to purchase consoles due to the sole reason of affordability.
This defeats NVidia on a higher level and benefits both AMD and Sony massively.