Iran is currently passively taking Western non-lethal beatings because they know they are the ones collapsing, on borrowed time, instead, probably waiting for stronger China to disintegrate them, in a final push, in the next few years.
Iran is a byproduct of the US being forced to act on them always due to Israel, whereas China is something that they really want from a survival perspective. Why would they take the lead in their opinion from their, Iranian, perspective?
They look for themselves first I think. Anyways, If Iran was truly about to collapse, then they would have been 10 times more emotional and erratic and urgent in their actions, something akin to current Israel. So, I'm not worried about Iran.