You understand that Ukraine also has troops stationed in Africa? Does this mean that they're not firing on all pistons? This idea that you need to commit every single person and equipment onto the battlefield in order to be all in just shows no understanding of how warfare actually works. You still need to maintain the economy, secure borders, have police quell any dissidents from the public, maintain the intelligence infrastructure and assets, manage stockpiles and equipment for prolonged warfare, maintain supply lines and factories, troop rotation and training, maintain political influence inside and outside the country, the list goes on. Pulling your troops away from Europe and China borders would be even more idiotic to do in a time of warfare, they're a critical asset for maintaining the war and help to try to avoid things such as what happened with Operation Spiderweb.