At best It will be Late 2021 and widely available in 2022. AMD normally use High Performance Node and Mainstream Node Pricing. And that is assuming there will be that many capacity left, as far as I can tell, ASML hasn't been keeping up with their shipment numbers. Possibly one reason why rumours are pointing to Apple using 4nm instead of 3nm in 2022.
What does moving to 5nm mean here? Starting to build stuff with 5 nm or releasing 5nm CPUs AND GPUs? Point is we don't know... and waiting for next gen is always an option -- what about next next gen?