I still struggle to see how Nelson loses in this environment, especially since he won by two landslides and Scott barely won, and Democratic incumbents in other narrow Trump win states are running away with it. I won't dismiss it out of hand, but it is confusing.
The Criminal was unpopular in 2010 and 2014, which was why he only barely won despite the waves. He's popular now.
Florida is a rather inelastic state, so I doubt popularity will get you that far. In a wave like this, with Florida's elasticity, Scott would need an approval of around +19 to win. That would be hard to accomplish.
