I think he's doing this on purpose. He'll endorse Desantis when it's all said and done. This is galvanizing the conservatives and moderates in the Gov's favor. I'd have a hard time believing he doesn't know it. He'll milk the next couple years for speaking engagements and such, campaigning, before he bows out.
I don't see why he'd want to go back to DC. It's worse than a swamp now, and it's only going to get worse from here. Desantis won't slow it down or stop it, even if he were able to win a national election controlled by 5-10 D run states.