I don’t think Iran is a proxy for Russia as much as Russia and China have interests in Iran remaining sovereign and trading oil in currencies other than the US$. It is more a proxy war with China than anything, considering they sell a ton of oil for Chinese yuan, but it’s more about long term strategic interests, everyone moving chess pieces to the middle for the “inevitable conflict” that no one really wants to fight.

I think it’s just the natural progression of what has been a very cold war between US and China.