Because Orlando still has Universal, I don't think we'd see a Rust Belt level of decline. Especially with
Epic Universe going in, I suspect that a lot of Disney fans would give Universal a try. So it would likely blunt the impact. But there would still be enormous shock waves. The massive increase in unemployment would likely tank the local economy, at least short term. Lots of restaurants/bars/hotels/smaller tourist attractions would close, causing even more unemployment. Housing prices would take a massive hit. The Florida Constitution forbids a state income tax, so I'm not sure where they would make up the revenue. I do believe that DeSantis wouldn't be reelected, but Florida has no provisions for a recall election, so he'd still be in charge for the rest of his (brand new) term.
I don't think that selling the parks would be as easy as some seem to believe. Granted it was never a cash cow, or a vital part of the city in any way, but
Six Flags New Orleans comes to mind. It closed for Hurricane Katrina in 2005 and never reopened. Yes, it was flooded and not incredibly salvageable without a full rebuild. But SO MANY developers came in over the years with big plans for everything from a shopping mall to an entirely reimagined theme park. And none of them ever actually happened. Literally a couple of weeks ago, 18 years after it closed, a final development plan was approved. Turns out that buying and redeveloping a closed theme park is an expensive, difficult, and extremely political process. And that's just ONE park, with no hotels or anything.