The warning signs were already showing by 2018, Scott only garnered 18k fewer votes in M-D than Trump did the first time while Nelson lost almost 150k Clinton 2016 votes. Compare with Crist/Scott seeing pretty much a wash in drop-off from Obama/Romney 2012 to the 2014 gov race. How does the FLDP find a way to make up lost ground with a demographic the GOP has consistently targeted under Trump?
For all the discussion of Florida trending red due to GOP gains with conservative Latinos, an equally important factor is the absolute collapse of the Democratic Party in the Big Bend and I-75 corridor since 2012. Do not let the 3rd-largest population in the nation fool you, FL has more than its share of rural whites. Florida's retirement communities powered Scott to re-election and in 2018 enabled him to unseat Nelson as much as improvement in South FL.