If you squint a bit, Russia is the proxy. China's to be specific. The outcome tested the waters a bit for how the international community might react to the invasion of a somewhat developed nation vs a developing one. It also uses up munitions and war chests of those that might get involved. And in the now seemingly inevitable case that Russia's economy and political power are severely damaged, it has a trading partner that makes plenty of food and fuel that everyone else has promised not to trade with, so the prices are cheap.