At this point, I doubt that DeSantis or any other among the R candidates will be the R nominee. The R convention is almost a year out, and much will happen between now and then. Anyway, even if DeSantis doesn't get the nomination (and he wouldn't be Trump's VP candidate, because that would forfeit FL's Electoral College votes), as long as he doesn't burn the wrong bridges, 2028 could be good for him.
Late November or early December may be "crunch time" for the Dems. It's pretty much the latest optimal time for them to ditch LIEden (+/- him being willing). So for Goobernor Noisome this debate could be a dress rehearsal for a wide open Dem primary season.
IMO, Hannity should keep the two on-topic, shut down ad hominem and straw-man arguments, and choose topics that allow DeSantis and Noisome to make clear what they are. If he does that effectively, it could set a pattern for the primary season and general election debates. That, at least, would be the potential. I doubt that Hannity or Noisome would reach that ideal.
If Noisome tries to attack DeSantis on abortion, he might be surprised with stronger answers than are given by tap-dancing-and-apologizing California Mo-o-o-oooderate Rs.