The point is Iran only turned to China because JCPOA failed. That's the kind of loyal partner you are getting with Iran. They are not comparable to China's relationship with NK or Pakistan at all.
China imposed UN sanctions on both North Korea and Iran. How can you expect "loyalty"? Iran, North Korea, Syria and Russia have all turned to China and each other because of western sanctions/bombs. They are also "loyal" to each other. Russia and Iran rescued Syria. North Korea and Iran have long cooperated on missile technology and maybe nuclear technology. Iran and North Korea are the only countries that have provided substantial lethal aid to Russia in its war in Ukraine.
China is slowly being pushed towards other sanctioned countries. You might regret it, but decoupling is coming and the number of sanctions on China are increasing every day. Other countries that are under similar or worse trade restrictions with the west are natural allies. The stronger and more stable they are, the better.
A multipolar world may exist in the future, but today we are clearly seeing the re-emergence of bipolarity. None of the other potential poles, like India, Brazil, Indonesia or Russia, are even close to strong enough to be an independent pole. Europe and maybe Japan might have the strength to be a pole but lack the will.
We may talk about multipolarity, but it's just a word that hides the real agenda: expanding and strengthening the pro Chinese pole while weakening western aligned countries. India and some African and south east Asian countries will take their traditional non aligned roles. 30 years from now, there might be a tripolar world with India or Indonesia joining China and the US. But the time for true multipolarity is not here yet
