I think Russias economy is hurting, as is demonstrated by the fact that Putin recently fired his defense secretary and replaced him with an economist. The oil refineries are burning. Putin is selling his oil at below market prices to China and North Korea. Most of the nations economic production is going to the war. A large portion of the working male population is in the army being shot at in Ukraine.
That said, Russia is no more on the brink of economic collapse than Ukraine is.
They are the forth largest econo.y in the world, passing both Germany and Japan. But a long ways behind US, China, India.