I looked extensively into earthships and other types of semi-underground housing for a project I am planning in Louisiana. I ran across this article:
https://theministryofarchitecture.com/earthships/tips-tricks-to-make-earthships-work/ about the pros and cons of earthships in different climates and it was pretty emphatically against the idea of any kind of underground housing in a high-humidity climate.
I also thought about historically how the pioneers in the area handled the climate -- houses off the ground, sleeping porches, houses with cross sections open to the breezes -- and I concluded that a lot of the natural building styles which are popular in permaculture are not that suited for hot, humid southern climates. Looking to the tropics for inspiration, especially since the climate in the area will be changing towards more tropical, is probably a better path forward for natural building suitable for this area.
I also think it might be a good idea to build a series of smaller, different types of structures for different purposes and/or different seasons of the year. For example, an off-grid bamboo hut enclosed by mosquito curtains and elevated off the ground might make for a lovely cottage in the spring or fall. Perhaps a partially underground shelter, or a soapcrete dome, might be a good winter building, and/or hurricane/tornado shelter. For the hottest days of summer, an on-grid tiny house with air conditioning might be the best thing especially for those susceptible to the heat! :)
