Impeaching him would be an absolute gift for Biden's reelection, given that they have failed to turn up even a credible suggestion of wrongdoing in two years of investigations. In all likelihood, they won't actually impeach -- dubious they can even get the votes in the Republican-held House, and the trial in the Senate would be massively counterproductive for them -- but just want to use the words "Biden" and "impeachment" in the same sentence for the next year.