Well, is there really a need for a Senate trial?
If McConnell makes a presentation of a vote on a Senate committee resolution declaring the House impeachment indictment to be an actual bill of attainder. He then can throw out the House case in summary judgement
I agree with you. With zero high crimes and accompanying misdemeanors, such an impeachment would be a bill of attainder which has the sole purpose of tainting the president. McConnell could declare it illegal and throw it out.