What semiconductor shortage? Who is affected by them? Russia is buying literally everything through Turkey, Kazakhstan and other ex-USSR countries. US and EU exports to ex-USSR countries are booming.
Of course Russia can't just sneak up some giant oil refinery or LPG equipment, but semiconductors are super easy to smuggle. Even more so since they have unlimited budget.
Which increases cost and lag time. It also means they’re restricted to commodity components; it’s even harder for them to have custom components fabricated.
Blockade runners have always been a thing. The point of the blockade is to increase cost, lag and uncertainty. That’s the difference between blockade/sanctions and siege.