Crist's performance in 2014 was actually very respectable given the environment & the fact that every other statewide race was a double-digit GOP blowout. I wouldn’t expect him to win, but also wouldn’t underestimate him or completely write him off. Republicans are very much favored, but this state certainly isn’t less competitive than IA or OH (either for Senate or Governor).
One key factor, though, was that Scott was very unpopular in 2014, and that’s not true of DeSantis at the moment. I agree that the FL races will be closer than the ones in IA/OH, and I don’t buy that DeSantis and Rubio will get authoritarian NUT maps, but I don’t think Crist, whose performances since 2016 haven’t been that impressive, would have much of a chance or would be a particularly strong candidate, especially given that he’d be running as a former Governor who already lost a gubernatorial race.