I wouldn't put too much stock in Saudi Arabia and Jordan joining a potential beat down of the Iranians. At the same time though neither intend to help the Iranians either. Saudi Arabia because there is no benefit for them doing so and nothing but downsides, and as for Jordan much the same. This was always the state of play for those countries even before October 7. Realistically, Iran's biggest allies were as you say. Syria, Hezbollah and Hamas. All three have been removed from the board.
That should have been Tehrans que to get up from the table and cash in what few chips they had left. But religious nut cases are pretty bad at deviating from a course of action once they have committed too it. Their only true trump card left was the untested nature of their air defense capability. Which in theory was developed to stand off an attack from the United States, which is capable of bringing in way more firepower then the Israelis. That it collapsed in spectacular fashion to a unilateral Israeli attack is honestly shocking. I don't think anybody expected that.
The whole game has been upended and Iran doesn't have anymore cards left. If they were smart this is the time to surrender. Its not checkmate yet, but the game has been decided and the checkmate is inevitable. But again, they are run by religious nutcases.