> MBS and the Saudis also want this

While it is true that the Saudis are hostile to Iran and do want Iran's power to be curtailed, they were never in favour of the current war because they knew the plan was ill-thought and suicidal for it, as they knew how Iran would respond (and how ill-prepared they and the American military was to defend them). Iran's foreign policy with its Arab neighbours is based on the blunt but simple principle - "Peace for all. Prosperity for all." Implied in it is that if any of the Arab neighbours upset the public peace in Iran and / or attacked its economy, it would retaliate to ensure they too wouldn't have any peace or prosperity. And that's exactly how it played out ...