What do you suppose they could do?
They need both chambers of Congress to pass a law or constitutional amendment, and they only have one. Biden could expand the Supreme Court, but he's too much of an old school statesman to rock the status quo, and there's no guarantee they'd vote as a unit.
Furthermore, Democratic states have been enshrining abortion access into law and/or their constitutions, and they've been getting abortion onto voting ballots in red states, so it's not really fair or accurate to say they haven't done anything meaningful.
Edit: typo