The CCP have a defense pact with Iran, and almost own Pakistan.
There is enough firepower in China and it's allies to certainly make it a war that embroils most of Asia, at minimum.
And if they are able to get Russia on side as well, then Europe may come under threat if Putin makes a play for the Baltics and/or Ukraine while the US is bogged down in the Pacific.
I hadn't known they had the defense pact with Iran; it doesn't really mean much of anything though, given Iran has no meaningful ability to project power outside of their immediate neighborhood. They could keep a carrier group busy for a couple of days gutting their navy and air force, but given that the Israelis would be happy to have unlimited license to deal with them, the US might not need to get involved at all.
Pakistan could distract India, that's fair.
Them getting Russia onside is beyond unlikely. It enters the realm of almost farcical. Putin has no illusions about who would win in China vs USA, and I'm sure they'd much rather ram through some economic concessions from Europe, or bite off another chunk of Ukraine that's small enough nobody else will be willing to go to war over it. If China and most of the rest of the world fights, Russia wins by default; getting involved earns them nothing.
Unless they go in against China, and like the opportunists they've been since Stalin, only attacking after China has clearly lost in order to seize some territory that, again, nobody else would care enough about to make them give back.
It is in Russia's interests to align with China in peace.
It's in their interests to step aside and sell them second-rate military equipment in war.
