The problem is saltwater intrusion into the drinking water table - a problem New Orleans only has one when it comes up the Mississippi river - Miami is a whole different level

That can be solved using desalination of seawater, an energy-intensive process which is tailor-made for the abundance of solar power in the area. If for some reason desalination is not deemed sufficient it may be possible to slow the seepage by creating deep barriers between coast and land [1]. If this results in groundwater emergence so much the better, just pump it out and send it to the water treatment plant. Excess water can be pumped elsewhere, either over the dikes or into the ground outside the dikes or wherever else it may be needed or beneficial. Since pumps are needed anyway the criticism in the article - reliance on pumps is costly and can lead to a point of failure in flood mitigation plans - is negated. Also, pumps have been used as part of flood mitigation plans for centuries in places like the Netherlands so there is a lot of data to be found for those who need it.

[1] https://coastalscience.noaa.gov/news/hardening-shorelines-ma...