The reason they built the enrichment site under a mountain was that no other site was safe from Israeli bombers. No one in history of world has attempted to obliterate a mountain. B-2 bombers with 230,000 lb bombs has never been tried before in a war. If anything, Iran had moved all other centrifuges to Fordow, thinking it was safe from Israeli bombers.
Someone would have told if it was moved en masse.
They can’t even hide nuclear scientists. I doubt they could hide convoys of trucks holding radioactive materials.