Here is another thought I just had.

Iran can't win against the US and you might think surrender would save them from being destroyed. But what surrender means is that the US will install the monarchy and then control Iran into attacking China... yes it will throw Iran at China, just like it threw Ukraine at Russia. And China will win and Iran will be devastated, but the US will have weakened China prior to any US-China war. So Iran will be devastated either way. Given this, there is no reason for Iran to surrender. From their perspective, they should just fight with all they have.