I don’t think you can blame Trump for the division in the country. For exploiting it: sure. But he didn’t create it.
I think that Democrats seriously misread the temperature of the country after the 2020 election. They thought they were granted a progressive mandate when really the voters wanted stability and competence with perhaps incremental progress on certain key issues. All evidence points in this direction, starting with the 2018 midterms when a slate of moderate candidates gave them a House majority (despite all the noise about a few celebrity progressive candidates). The moderate labor Democrat Biden was the nominee over Sanders and Warren, etc.