Does anyone really think that the US government would be prepared to give up sovereignty over so much as a square foot of its territory? Or a state either?
Claiming some part of the US to be exempt from US laws is how that dustup in 1860-65 came about, isn’t it?
You’d have to go to some poverty-stricken hellhole country and get them to sell you part of their country. Then you’d have a plot of land in some pestilential paradise. How could one resist??