I don't realy think you could say that it was down to democrats being uninspired. Desantis was a polarizing national figure, if it was a 9-10 point loss that could he been plausible but Christ lost by more than 20 points. There has to be something deaper beyond him simply being an uninspiring canidate.
As noted above, DeSantis added about 500k votes to his 2018 total while Crist fell just short of a million votes of Gillum's total. Even if we assume those ~500k new DeSantis voters
all voted for Gillum in 2018 (extremely unlikely given the state's notably rapid growth), the remaining dropoff and frankly pitiful final vote count for Crist (a statewide Democrat barely breaking 3 million votes in post-2016 Florida in a high turnout election is simply embarrassing) represents a catastrophic turnout failure. No other real way to look at it. Whether it's Crist being uninspiring or the state party not knowing its right hand from its left is certainly worth a conversation, though.