Iran is the 'final boss' of the Middle East in US military geostrategic thinking/policy papers in controlling the global oil trade after eliminating all enemies/oil wealthy middle eastern countries in the region by co-opting them with regime change with pro-US dictatorships. US military and think tanks (funded by oil & gas, MIC, multinational corps, investment funds etc) has been interested in a war with Iran since they built the bases in the GCC countries. I remember when I was growing up as a kid there was news stuff on TV about "Will the US eventually invade Iran" due to the base building? It took 25+ years for it happen. Iran is the final boss in US military war games because it was perceived as the strongest enemy to defeat militarily.... Russia and China do not want the US to completely take over middle eastern oil (Russia is also obsessed with the concept of "Buffer Zones" as they do not want a US-NATO backed regime change operation in Moscow, which is the main reason why they launched a pre-emptive invasion of Ukraine). I also believe that's why Russia propped up the Syrian regime and initially had the upper hand until they got bogged down in the Ukraine. Iran is very important to both Russia and China so they definitely don't want a successful US regime change in Iran.