C
China has strong relations with Iran, a lot of trade, a lot of military hardware and missile tech knowledge, China get cheap oil in return and the chance to poke USA in the eye.
Trump was keen on maintaining sanctions against Iran which limited Iran's ability to fund terror, The EU dropped the sanctions in return for Iran postponing it's nuclear ambitions for a couple of years and one of Bidens first jobs was to rescind trumps executive order and lift the US sanctions on Iran.
It's a *****d up world out there, if Israel are reigned in too far, it'll be even more so.