I think for anyone open to reason, @Timodc offers a fine list of reasons to come to their senses. But I am more pessimistic than he is: I don't believe the people who are now still leaning to Trump are accessible to reason.
There is only one appeal to make, imo. /1 https://twitter.com/SarahLongwell25/status/1320389737992146949

It is the appeal to your own innate moral sense. To ask yourself if you really believe that everyone else - Biden?! - is so evil that you must support Donald Trump. To examine your own heart and to ask yourself if you really are the kind of person who believes such a thing. /2

Of course, if you are the kind of person capable of even this much introspection, you've probably already decided and you long ago realized that your own moral sense gave you the answer about why you cannot support Trump, even if you're reluctant to actively fight him. /3

But to list policies, or Trump's crimes, or the roster of thugs and goons that have led to so much death and chaos, is pointless. The answer lies not in the brain but in the heart. And that's not a policy argument. That's a basic "what kind of person am I" question. /4

If you're capable of asking that question about yourself - without dodging behind "but abortion" or "but guns" or "but President AOC in 2032!!" or any of that crap, you've probably reached a moral conclusion. But maybe - maybe - you haven't had that talk with yourself. /5

At this point, imo - despite the perfectly sensible appeal @Timodc and others are making - that's all that's left. One more dark night of the soul and honest moral introspection before voting. It's all we can hope for now. /6x