One view of the future:
2022
DeSantis really leans into Trump, getting a big endorsement and a big Trump rally, but surprisingly only wins his gubernatorial race by a relatively thin margin. Rubio gets the Trump endorsement, but generally keeps his distance and plays to the middle. He surprisingly beats Deming's by a wide margin and is suddenly the Florida golden boy again.
2024
Rubio considers another presidential run but in the end decides to pass. Trump doesn't run. Rubio gives DeSantis an obligatory fellow-Floridian endorsement, but mostly keeps a low profile. DeSantis runs a garbage campaign and the nomination eventually falls to Mike Pence, who inspires no one but is nevertheless universally well-known. Pence is running against a semi-popular incumbent Biden and knows he can't win without Florida. DeSantis is a loser, but Rubio has a strong track record in the state, so Pence picks him. Picking Rubio also serves as an olive branch to the DeSantis folks, given Rubio's earlier endorsement.
Seems possible. Pence/Rubio would be something I'd be glad about, but I'm not sure if Rubio would conceivably stay out of a no-trump race. If I was on his team I'd push for a second run.