As a last resort she could refuse to seat Republicans who had won their elections so that their states would have Democratic majorities in the House. But that might be just a step too far for them to expect the country to accept...putting Biden in the White House because duly elected Congressmen were prevented from voting.
There is no end to what she will try to pull, in order to keep her own power, or to put herself or her party into the White House.
What can she actually do (legally, or perhaps illegally but with the complicit support of the media), and how will her actions affect the final outcome?