You forgot the most important thing, especially for war. Oil.
China imports a fuckton of it. But not from Russia, but the Middle East (by sea) because it’s cheaper and easier.
It’s actually very difficult to move that much oil over land. The best way is by pipeline but that takes many years and is fairly easy to disrupt. And it still leaves you with the problem of having to distribute it at the other end.
I personally do not think it is that difficult. It is indeed more expensive compared to sea transport, definitely (I said the same thing regarding the transport of grains in another comment), but it's certainly doable.
In case of a war starting I do think China won't look at the money getting spent anymore, so at that point importing oil from Iran via train [1] or from Russia (again, via train) won't be a problem for them in terms of money.
I also do think they'll switch to "war economy" mode pretty soon after the war starting, so no more private cars on the roads and such, which will greatly alleviate China's oil-related needs.
Later edit: And there's also the Northern route. I don't think any US aircraft career will be brave/stupid enough (depending on how you look at it) to position itself close to the Sakhalin Island or close to Kamchatka, that's prime hunting ground for the Russian subs. Never mind going into the Arctic Sea itself.
China imports a fuckton of it. But not from Russia, but the Middle East (by sea) because it’s cheaper and easier.
It’s actually very difficult to move that much oil over land. The best way is by pipeline but that takes many years and is fairly easy to disrupt. And it still leaves you with the problem of having to distribute it at the other end.
Now consider grain can’t flow in a pipe.