Nationhood, but really we’re talking about sovereignty, isn’t something you can just declare. It’s something that’s granted by others. Sometimes it’s through agreement. Other times it’s by fear of force.
That’s why I was always skeptical of things such as the Seasteading Institute that wanted to declare a cruise ship a country, and then have the “populace” commute to San Francisco. That plan works, right up until a US Coast Guard cutter pulls up and sends over a boarding party.
The sea floor is littered with this folly.
Republic of Rose Island. Seized the the Italian Finance Police, and sank by the Italian Navy https://en.wikipedia.org/wiki/Republic_of_Rose_Island
The Republic of Minerva. A reef island 250 miles from Tonga. Evicted and claimed by the Tongan Navy. https://www.atlasobscura.com/places/republic-of-minerva
Sealand. Raided by pirates, but honestly ignored by the U.K.
Putting aside the varying seriousness and motivations of micronation would-be-founders, it’s hard to judge the history of such endeavors[0] as being anything other than failure.