Unless you're regularly mingling in Republican-land I think a good deal of people on the left don't actually understand the dynamic Trump plays with the Republican party. Everybody knows Trump is an asshole. Almost all of his voters are completely aware of this. I would be willing to bet that more than half of the people who vote for Trump don't actually even like him on a personal level. People who vote for Trump do so as a shield against the things they do not like on the left. That's it. Republicans feel threatened by the left and Trump is the savior and it doesn't matter what he does or how he does it so long as he shields them in the end. He can shoot someone in the middle of the street or grab you by the pussy, it doesn't matter, he's still going to get votes because liberals are that much worse. There's no mystery nor secret here, it's honestly that simple. Humans love making things complicated.
As for DeSantis / Trump, if Trump runs they're going to obviously vote for Trump. But Republicans at this point would like to break free of Trump's baggage and DeSantis is a clean slate and by doing shit like shipping immigrants to Martha's Vineyard, to taking on Disney, declaring war against 'wokeism,' so forth and so on, Republicans love this shit. If Trump and DeSantis go head to head DeSantis will win. I personally know of exactly zero Republicans that want Trump over DeSantis, even prior to the win in Florida they already wanted DeSantis. I'm even including Trump supporters I know who have attended Trump rallies.
Here's a fun experiment. If you know a Republican ask if they want Trump or DeSantis. The answer isn't going to be Trump. If DeSantis wins the R primary and runs for the presidency then Democrats might actually see that supposed red wave that was alleged to occur the other day.