They impeach, fail to remove from office, and he wins overwhelmingly on total exoneration because his supporters are fired up. The ad is ready made.
His supporters aren't a majority or anywhere near.
His hard core supporters are probably less than 30% of the electorate.
Look, I realize that Trump gets you excited, but most people look at him like a bad movie they can't wait to end.
That's what everyone thought in 2016. If the democrats don’t put up a candidate that generates more excitement than hapless Hillary, the voters will stay home and Trump's in for another 4 years, ESPECIALLY if he's found not guilty.