Not clear yet why she did. I did see some speculation that she's trying to work around SCOTUS and force the admins hand. SCOTUS said the states objected before any actual harm so they had no standing, so by lifting her stay it allows Trumps people to go forward with the voter suppression plan. And then if correct, she or another federal judge will then jump in off one of the many lawsuits and put an injunction saying you can't do this, causing harm, too close to the election and SCOTUS won't be able to claim no standing?
Otherwise we all have to hope we're on the list to vote and if not, we have to be willing to vote in person