Fighting a 3rd world country is a little bit different than fighting a European country armed to the teeth with American weapons. The death count for the Ukranian conflict could be 7.88 billion if Putin decides he has nothing to lose. I am not sure painting the country with the largest nuclear arsenal in the world into a corner is superior to a negotiated peace treaty that allows him to save face.
It is also notable to see countries like Brazil, India, Saudi Arabia, Iran and China all being neutral (at best) on this conflict. Saudi Arabia has signaled an interest in moving away from the petrol dollar,. If that occurs, it could signal the creation of BRIC coalition in opposition to American power. That would pretty much signal an end to America's ability to project power.
The war in Ukraine has precipitated the recent strengthening of the BRICS group, which could challenge the current Western-led world order.
www.americansecurityproject.org