The biggest losers beside Iran will be big Muslim countries like Egypt and also both Pakistan and Bangladesh if this war keep continuing, as both rely on import for energy with large population and also remittance from Middle East countries to defense their currency as both have big trade deficit.
Gulf nations with big US Dollar reserve and low population will be able to come back as soon as the war stop
USA as big oil and gas producers are not really damaged with energy skyrockering relative to other country ( And their country is not getting bombed like Iran )