Military pay, ammunition, tanks, planes, and compensation for dead and wounded soldiers, all contribute to the GDP figures. Put simply, the war against Ukraine is now the main driver of Russia’s economic growth.
And it is a war that Russia cannot afford to win. The cost of rebuilding and maintaining security in a conquered Ukraine would be too great, and an isolated Russia could at best hope to become a junior partner entirely dependent on China.
This feels like the aside in Hitchhikers Guide to the Galaxy about the planet that became economically incapable of building anything but shoe stores, but if it was written by the Orks from 40k.