Harris is a non-factor. Even Democrats who dislike her for their reasons from the left will still vote Biden over Trump. Biden matters only so much if he’s acceptable to those who want a break from Trump.
Trump wins if the American public trust him on three issues I see... economy, the virus factor, and the civil unrest. This court issue, as much as it does matter, is going to be behind those three to the masses. GOP senators will kick the can. Everyone who is running wants to get reelected, limit as many factors that can put you in a bind. Thus, the Rinos provide cover. It’s on President Trump to make his case.
What’s ironic (unfortunately) is that the Republican SCOTUS picks have been so unreliable in landmark cases that very few intelligent people probably see the Supreme Court as a major campaign issue anymore.