The novel I’m working on briefly describes some remaking of this country. I had fun with it, but I’m not sharing any spoilers.
The only country I would consider making would have to belong to me, so other inhabitants by invitation only.
To establish my own country, it would have to be Bir Tawil. It is the one habitable unclaimed land on Earth.
To claim Bir Tawil, a government would have to be established, and permanent residents living there. Permission to be recognized would have to be obtained.
So, claiming Bir Tawil would require people who don’t mind the climate living there. I would have to explore it carefully to see whether it has any natural resources. So far, nobody has bothered. Next, I would consult Sudan and Egypt, to see if either would allow me to claim, or use a narrow swath of land to the coast. That would not bring fresh water, nor sea water to my country, so no fish either, but it would provide coastal access by boat or seaplane, rather than a lengthy ride through treacherous desert.
A water source would have to be discovered deep in the terrain, or somehow provided.
I think the only way to have residents would be to open a bank. With no potential for agriculture, and not likely any business willing to build there, a bank could be established with protection against law enforcement investigation. A few wealthy people might be interested in using the facility in return for declaring citizenship. If I could make available transfer of all African currencies, it could become a go between.
It would leave me a life of leisure. Nobody would be around much, but I would have plenty to have responsibility over.