You're trying to spin this as something the US wants, but it's not. It's something Putin wanted. Zelensky and the people of Ukraine are (obviously) far more determined to defend their country than anyone else. And many European countries are mostly supporting Ukraine because their own citizens are demanding that they do so.

There's tons of popular support for Ukraine, because most people recognise the terrible injustice of the Russian invasion and the atrocities committed by Russia.

How things will look after the war is impossible to predict, but US support has helped western Europe quite a lot after WW2. And even the defeated enemies of that war, Germany and Japan, are doing extremely well because of the way they've been rebuilt after the war. In the long run, the best outcome for Russia would probably be to be utterly defeated and rebuilt the same way. But of course that can never happen because Russia has nukes.