Either DeSantis will figure it out, or he won't. There is no other realistic candidate out there who can challenge Trump. Most of the other candidates are campaigning for VP, or a place at the table after the election.
If DeSantis can't beat Trump in a primary, then he probably cannot win the general election, either, notwithstanding what the DeSantis supporters are saying.
A recent poll has DeSantis within 25 points in Iowa, better than he had been tracking, so maybe he is starting to see some momentum. There is a lot to like about RDS: military record, age, family man, good credentials and rock-solid conservative. The question is whether loyalty to Trump obscures all that or not. It could be a majority within the GOP are loyal to Trump, and no one can wrest the nomination from him. That will be tested, and it has always been a quixotic pursuit.
My big hope is that if DeSantis loses Iowa, he backs down and they make up, and we can get on with taking the White House back. The worst thing would be for DeSantis to lose Iowa and then keep fighting. If DeSantis can somehow take Iowa, then it will be a bloody battle until at least Super Tuesday and maybe beyond.