When does this end?

When Russia is defeated.

How is the US benefitting from this?

It's sending a message to authoritarians. Don't invade countries or we'll send the other country stuff to make it go badly for you. This has a chilling effect on authoritarians, making them refrain from this kind of activity. This improves global security, which results in better trade, which improves the global economy. The US being on the globe benefits from this.

Also, do you like how much you're paying for groceries? Could it be this war is causing a disruption in grain supply? You know that stuff that goes into bread, the feed that cows eat, etc? Yeah, I know people on the internet are all blaming their own governments (in basically every country, LOL) for high grocery prices, because no one wants to say that's it's Putin. Sure there is probably some assholes jacking up the prices more than necessary, but do you think all the corporations and all of the governments got together and decided to do this? Nope the inflation, the high grocery prices, it's because of Putin's bullshit.

Not to mention all of the influence campaigns Russia is running on the internet. You know where you're constantly being influenced by the internet towards burning down the capital of your own country? That's a disinformation campaign designed to destabilize NATO countries. Taking down Putin will lessen that buillshit. I say lessen because after seeing Russia's success other countries like China are getting in on that game now too. But one asshole at a time.