Trump placed sanctions on the company building Nord Stream 2. It was not completed until after Biden removed the sanctions. Your premise of the U.S. selling gas to Europe would have been met by keeping Nord Stream 2 from going online.
Regardless of the culprit, the goal of taking out the pipelines was to reduce Russia’s income from selling gas to Europe. This was to be a penalty for the transgression into Ukraine and a financial hindrance of funding it’s military.
But Biden did tip his hand before the incident.