There never was a Democratic majority congress. West Virginia and Arizona both sent senators who had a D next to their name, but were really Rs.
Not only that, but you need a super majority in the senate to get anything real through, which means you need 60+ Democrats who ALL need to be on board, along with a majority of Democrats in the House, AND a Democrat president.
That hasn’t happened since early Obama, and he squandered it by trying to pass bipartisan legislation with the Republicans, instead of just railroading the right things through.