That's not what deterrence means. From google: the action of discouraging an action or event through instilling doubt or fear of the consequences.

It's meant to avoid conflict altogether, say with China and Taiwan.

Iranian here, you're assuming sanity.

That doesn't work when your opponents pray for death and see martyrdom as victory.

This is genuinely how Shia extremists think. They have nothing to lose and will sacrifice everything and everyone for their cause. They don't care about Iran or Iranians or prosperity of the nation.