Australia operates 6 antique diesel submarines. Its contract with France was farcical and ended in public acrimony. Do you think they'll be able to successfully build and operate any number of nuclear submarines, even with American hand-holding? If this contract has any chance of succeeding they'll be getting American submarines, built in America, and sailing under American command. So, basically, an American submarine with an Australian flag painted on it.
By contrast, if Argentina gets JF-17s, they'll be purchasing an excellent budget fighter well within their capability to operate and maintain. So you're right in that the purchases are dissimilar - the Argentinian one has a much better chance of success.
Frankly, the most out there thing going on in this forum recently has been people taking this AUKUS thing seriously. I feel a joke coming on: a fading hegemon, a long-faded hegemon reduced to a flunky, and a penal colony walk into a bar...