This is a good example of what are essentially 'jamil says ...' assertions that when challenged to support with citations you never doMore people voted in 2020 than ever. It was a highly contested election because both sides thought a lot was at stake. The support for Trump lessened among independents by 9%. Trump's leading the pack by a lot among Republicans, but what that says is that ~half of Republicans would rather have someone else.
Die hard Trumpers are maybe 30% of the vote. I don't see from what other Demographics Trump can get votes. He did better among Blacks and Hispanics, but not enough to matter, because they still went for D's hard. Trump will probably lose even more ground to young people. The new young adult voters have been indoctrinated. They won't want to go vote, because they never do. But the fat pink haired lady will be along to convince them Trump is literally Hitler.
BTW, DeSantis has broad appeal. Just not among die hard fiercely loyal Trumpers. And that's actually the difference. DeSantis also actually has a track record of beating the "margin of cheating" in FL. He learned how to ballot harvest and did it well enough in Dade county, of all places, to make that a fair fight. But like I've said. This ain't about DeSantis. It ain't gonna happen for him this trip. So it would be nice if Trump could actually have wide appeal and get support from people who aren't fiercely loyal Trumpers. That ain't gonna happen unless he can fix that image problem.
Here are a couple of actual citations, from RCP. These are general election polls and presumably include Dems, Reps and Independents, so 'broad appeal' should be apparent, yes?
Trump, who supposedly couldn't beat Biden has closed the gap to a virtual dead heat in the poll average
Biden 43.8 Trump 43.6 for Trump -0.2
Worst result Biden +4, best result Trump +6, with Trump moving in the right direction
DeSantis, who supposedly was the only one who could beat/was beating Biden is moving in the wrong direction, losing his perceived advantage and falling behind
Biden 43.5 DeSantis 42.0 for DeSantis -1.5
Worst result Biden +6, best result Desantis +1 with DeSantis falling away
Again, general election poll, should include full spectrum of the electorate and 'broad support' should be apparent