2GB GDDR6X chips do not exist. So the only way to do a 20GB 3080 now is with 3090 type design. £££
16GB 3070 can however be done simply with the existing PCB.
thought the 3080 and 3090 boards were identical as well?
even if they aren’t it’s pretty easy to use a 3090 reference board to make a 20gb 3080 super vard