Russia and Ukraine

[Thumpalumpacus]

Only maybe 50 are on intercontinental ballistic missile that can reach the US.

That's enough for the sake of deterrence. Look at how NATO is trembling at the thought of a tactical nuke being used in Europe.

Additionally. Chinese SLBMs have a range of 7,000km, so discounting them is not very useful. All told, they appear to have around 250 warheads capable of targeting American cities as far inland as Dallas, and the SLBMs could obviously reach further.

Here's the chart I'm basing this on, from the Bulletin of Atomic Scientists:



As for the rest of your post, I think you're fundamentally misreading the shift in power between Russia and China that has happened in the last three decades. Power is economic as well as military as a measure. Deciding to positively stay in Ukraine will only sap Russian military and economic strength, making Putin's regime more unpopular and at best nudging Russia into the status of Chinese vassal as a matter of economics. Those tanks and planes ain't gonna pay for themselves.