That didn't "leave it until now" - they were more or less forced into a redrafting of the previous indictment to take account of the Supreme Court's recent presidential immunity ruling.
It's basically the same charges as in the case that was already before Judge Chutkan but with any reference to conversations with Jeffrey Clark and Mark Meadows removed, since these conversations would be covered by the new interpretation of presidential immunity issued by the Supreme Court.
Judge Chutkan was supposedly already in the process of reviewing the previous indictment to see if any parts of it might need to be struck down because of the Supreme Court decision. This new indictment just saves her the trouble of doing so.