One could argue, but it would be a stupid argument.

China buys oil from Iran. This is not "supporting the IRGC". This is "buying oil because China needs fucking oil and is willing to circumvent bans to get it". China uses about 16 million barrels of oil PER DAY. 70% of that is imported. The Arab states are locked tight by the USA and its allies. So China buys from whoever is left. Which, realistically speaking, means Iran.

China sells military equipment and satellite time to Iran. This is not "supporting the IRGC". This is "selling goods".

Are there political motives? FUCK yes! There's political motives to any trade anywhere between any two countries. But it's a HUGE stretch to go from "China sells weapons and buys oil" to "China is using Iran as a puppet state". (For starters, why the flying FUCK would China tolerate a puppet state taking actions that threaten its own energy reserves? If Iran were an actual puppet state, the Strait of Hormuz would have been opened right the fuck up. The Chinese government really doesn't like the unrest that sudden price increases across the country causes.)

Let's shift the nations involved and test the sound bite:

• The USA sells weapons to Denmark. Ergo Denmark is a client state.
• The USA buys oil from Canada. Ergo Canada is a client state.

See how idiotic that sounds, especially given that Denmark and Canada both are rather pissed at the USA and are pushing sanctions and boycotts?

When you see Chinese soldiers on the ground in Iran, perhaps as "advisors" or as "instructors" or the like, then maybe we can talk client state. When you see Chinese frigates patrolling the coast of Iran on its behalf, then maybe we can talk client state. When Iranian naval vessels do drills with Chinese ones in the China Sea, maybe we can then talk about client state. When there's Chinese military bases in Iran, then maybe we can talk about client state. Until then any talk of client state is geopolitical gibberish.