Russia is only withholding oil from countries that refuse to pay for it (a few Euro ones). And even those countries still buy it, just at jacked-up prices through a middle man. This is a great example of western propaganda in real time, because this situation is always characterized as Russia actively trying to screw over Europe, rathee than European countries sanctioning Russia and therefore refusing to pay for the oil they ordered.

Rusdia is in a decent economic situation for a few reasons, though keep in mind they are capitalist and exploitation and suffering were therefore already the order of the day. They can make tons of money off their oil, still, through higher prices for Europe and more volume to China and India. They have robust trade with China, so consumer and industrial goods are still available. They have a decent industrial base that they are attempting to rapidly expand. They have a monetary policy that is okay. Still lots of dumb capitalist shit, but they have recognized that they need to do more industrial capital and infrastructure development, plus getting threatened by the US for a decade with fiscal weapins has led to heavy investments in BRICS and USD-independent payment and clearing systems.

The simple version is that Russia has a decently-sized "real" economic base on top of their massive oil exports and have protected themselves decently well from international finance capital, plus their internal fiscal policy has just enough planning rejection of neoliberal approaches that they aren't actively tanking their economy for the sake of line going up (which, ironically, also makes the line go up).