Nukes don't give Russia infinite resources. Russia's economy is suffering. They've mostly ran out of modern tanks (except for the T-14 which still hasn't seen combat somehow), they're using donkeys for trucks now, their artillery has lost the punch it had two years ago. They're mostly sending demoralized soldiers in deadly human wave assaults, and dropping bombs on cities. That's all they've got left.

Russia has the economy of a medium-sized EU nation. The EU is vastly more powerful. If the EU wants to, they can give Ukraine everything they need to win. Only they're divided and unwilling to believe in their strength after 80 years of dependency on the US.