Every journey starts with a single step. This journey can be accomplished in batches. Coordinated batches.
Launch sites will have to be taken out first and that can be problematic.
It’s a long flight. Sub capabilities notwithstanding.
Even still........
Depends upon when they start deploying functional warheads.
Flight-wise, they’re at max range even with extra fuel tanks.
Maybe if the Saudis allowed refueling tankers. Of course they fear Iran’s mullahs as well.