It's a war economy. Russia builds a lot of tanks, mans a large army, pays a lot to the families of the fallen, it all adds a lot to the GDP.
But those tanks are going to burn, they don't add value to the economy, won't be exchanged for foreign goods. If you dig a hole into the ground, you increase the GDP, war destruction is not much different in its value creation. GDP is not a perfect measure of an economy.
A) Russia is large enough that it doesn't really need foreign trade to have an economy
B) We -- ie "the west" have no control over what India and China does wrt russia. If they keep buying Russian oil, we can't stop them.
But those tanks are going to burn, they don't add value to the economy, won't be exchanged for foreign goods. If you dig a hole into the ground, you increase the GDP, war destruction is not much different in its value creation. GDP is not a perfect measure of an economy.