They'd have to move left on economics and deemphasize and/or offer a moderate solution to social/"woke" issues, while caring about the problems that impact minorities. Presenting themselves as a moderate alternative to the Dems like what The GOP did during the '30s/'40s would be the only way to win at this point, barring a devastating administration ala. Truman-style or an extremely popular GOP nominee. I cannot think of a GOP nominee right now who would win based off of bipartisan popularity (not even someone like Romney or Cheney), but I'm sure they'll be someone someday.
If the election was held today I think a few would but they wouldn't after a whole campaign of attacks.