My view is that preventing economic integration of Europe with Russia and China was one of the main motivations on the part of the US. However, I also think that they initially believed that Russian economy would collapse in a few months once they cut Russia out of the western financial system. This idea was premised on using nominal GDP to evaluate economies, which has become part of mainstream dogma in the west. Russia has always been dismissed as a gas station with nukes, and its economy was supposed to be comparable to that of Italy. This is basically why the Europeans got onboard with the project. The promise was that Russian economy collapses under sanctions, and then they'd get the repeat of the 90s where western companies would get to plunder Russia.

Obviously things haven't worked out that way, but I do think that US likely sees this as the least worst option. They're going to lose the war, but they got to plunder what's left of the European industry, and destroyed European economy for decades to come. This is basically US doing a scorched earth strategy as they retreat from the European theatre.