Why is Russia “on the verge of economic collapse” in its war against Ukraine, but the USSR was able to persevere during the early ’40s in their victory over fascism?

WWII was much bigger than the Russian Invasion of Ukraine. About 27M Soviets died back then – and about half were ethnically Russian – and today, about 1.3M Russians have died in this war.

But more starkly to me is that there didn't seem to be a fear of an economic collapse in '42 as there is now. Why is this?