I think you have to put things in perspective.
China lacks water, and oil. It is not in good shape to either feed or provide energy for its people. Russia has lots of oil, and good relations with Iran. They are also planning to build an arms resale capability, and they are looking to Iran as one of their customers.
Please review the new pipeline projects in Iran, and the implications on the Straights. It is too granular to go into on a web site. You will find information on the web.