The reality is that it was up to the member states to pressure China in early 2020 to release the information they should have shared. And as the only member state as large or larger than China, this was the US’s job. At the time, however, the Trump administration was entirely focused on closing a trade deal with China that Trump could use in his election campaign. Which is why the US said nothing which prevented the WHO from getting the support they needed to investigate the origins of the pandemic.
For the first few months the US, and especially Trump, was basically going on about how well Xi Jinping was handling everything.