For the sake of a thought experiment, what if Iran actually 'was' found to have the bomb? And instead of just two Western countries, the ROW decided it would be a good idea to remove the government and the weapons.
I'm looking at it as a Seldon Crisis, where the first two were solved by intellect and patience.
China would be the key player since it buys 90% of Iran's oil. Russia could easily replace Iran's share of imported oil. There are already pipelines between Russia and China, and one more would supply China with even more than they currently get from Iran.

I still think that world leaders quietly applauded Israeli and the US for taking action. Poor Mark Carney had to walk back his support when he saw the ROW virtue signaling.
I think the JCPOA was a pair of beer goggles, and Iran turned out to be coyote ugly.