The problem with South Florida isn't that the sea level will rise enough to directly flood everything with seawater but rather with drainage of rainwater. There is already only a small gradient for rainwater to drain off into the ocean. If the ocean level rises even a little then drainage slows and flooding increases. The whole region sits on a karst substrate so dikes aren't effective; they'll need active pumping.

Ok, well 'most of the Florida Peninsula' is significantly above 2m elevation.