In a bizarre twist, the conclave has decided to elect a random Atheist as pope - believing they will show the world that Atheists don't have any better answers than octogenarian celibates. You've been selected - what would you do?
Remember, disbanding the church really isn't an option because the adherents aren't going to give up just because an Atheist Pope said to abandon faith. Realistically, what could you do as Pope that would actually have a positive impact on the world?
So the conclave decided to try to show how bad an atheist pope would be.... I would double the irony and implement full biblical law as described in the bible... show them how they sound to us when they drone on about their "morality".
Unfortunately, I don't think I could live with actually condemning people to death so I would probably put a stop to it at that point.
Admit that the overwhelming balance of probability is that god doesn't exist. Sell off the assets to establish trusts to help medical, scientific and social programs such as vaccinations, contraception and access to healthcare. Open up the Vatican libraries and sealed documents to public scrutiny.