Not to mention, many parts of Miami are already built on artificial land. My uncle's place is in East Fort Lauderdale, which is an artificial network of peninsulas. sort of like this [1] but connected to land. New houses are build higher. Realistically I think accommodating rising sea levels is going to be accommodated incrementally by new development.

1. https://en.m.wikipedia.org/wiki/Palm_Islands#:~:text=The%20P....