I have lived and worked in China.
My speculations are based upon experience with people there. They were not stupid people at all. They were infused with a cultural-inspired vindictiveness that could make them quite capable of self-destructive factional disputes at the moment of their greatest victories.
We have analogous weaknesses in our own culture.
I stand by my expectation that first use of nuclear weapons in this century will be China vs China.
Sure, of course. lived in China before Xi does not count. Different country different rulers. Emperor Xi will not use nukes and neither will any of the other PLA factions.
I do not discount that possibility.
However, if Iran gets nukes, which looks increasingly likely, barring several consecutive Trump policy Presidencies in the US and / or continued Israeli success at espionage, such acquisition almost certainly leads to a ME arms race that can have only one result: I’d say the only question would be whether the initial exchange is between Israel and Iran, or, more likely, between Sunni and Shiite factions or countries.