Furthermore, more inter-state conflict does not mean that trade stops nor that the US has to be involved with one or the other of the parties in conflict.
The US is the main advocate of cutting off trade with nations that we have an actual or possible conflict with. Other nations seem happy to continue trade, e.g. I believe that gas is still flowing to Europe from Russia via Ukrainian pipelines.
And other countries avoid identifying parties to conflicts as their own friends or foes. e.g. China is avoiding that in Ukraine and Israel.
Ironically, yes. Moscow needs the foreign exchange, and Ukraine would not benefit from cutting supply to supporters in Europe.
Another more obvious critical item we import, and I forgot, is bauxite, the ore from which aluminum is extracted. Our domestic supplies are small and expensive to mine.