Russia is fighting the war exactly how I would expect an economy of that size to fight a war. Slow attrition coming from an inability to overwhelm their enemy decisively and fast.

How exactly is their economy "strong"? By what measure? You cannot really eat tanks, that is what made life in the Soviet Union unsatisfactory as well.

Current price of Ural oil is some 9 dollars above their breakeven costs. As the classic says, not great, not terrible.