Yes! Let's repeat 2008 and 2012 all over again guys!!
Two questions for you:
[1] How is DeSantis ("someone else") going to make up for the conservatively estimated 10+ million voters that will not show up for DeSantis ("someone else")? IOW, the "only Trump" voters...
[2] Which "rust belt" state is DeSantis ("someone else") going to win, and how will he go about winning it?
I happen to live in one of them (Wisconsin), and I can tell you that DeSantis would lose here by at least 10 points because many disaffected working class people (such as myself), disaffected farmers, and disaffected trade union workers, especially along the western side of the State and in the northern section of the State, wouldn't turn out for him like they would for Trump. They'd either write in Trump's name, stay home, vote third party, or even vote for Biden again. Without those votes, Wisconsin will, like it did in 2008 and 2012, go solidly blue. Trump turns out (in masses) a disaffected and diverse working class coalition that the professionally Republican simply cannot turn out even in their wet dreams.
Without Wisconsin (and/or other "rust belt" states), DeSantis ("someone else") has NO viable path to 270. Meanwhile, Trump won Wisconsin in 2016, was frauded out of it in 2020, and if fraud can be overcome via a different strategy in 2024 (ballot harvesting, early voting, etc... anything to reduce the "leftovers" on the voter rolls that Democrats can take advantage of), then Trump would win Wisconsin by at least a few points, if not 6-ish points.
What you are proposing will result in a Republican Party fracture that will put 1992 to complete and utter shame.
Enjoy the bugs... slava ukraini!