DeSantis. I've wanted a Republican with relatively "trumpy" policies and ideology, but without Trump's personality and flaws for a really long time, and DeSantis is as close to that as it'll ever get.
I do not, however, believe that he would be an electoral juggernaut. He doesn't have a lot of charisma or charm and based on his staunch conservative policies, his crossover appeal will have a low (but electorally sufficient) ceiling.
In particular, I don't think he would have the same kind of appeal to white working-class voters in the Rust Belt as Trump, which complicates the electoral college math quite a lot. If DeSantis and Biden split the popular vote 50:50, I can easily see the resulting EC map looking something like this:
https://www.270towin.com/maps/w8r1QHe would nonetheless be a stronger candidate than Trump, who has jumped the shark a long time ago and is too politically toxic with too many crucial groups of voters.