Think of being a nation has part of being a club. You.r not a member of the club unless other members say your a member...
Whatever happens as a member or not in a club (a cheesy comparison imho, friend!) you're a citizen of a Nation merely by embuing the requirements of citizenship for that Nation. That's by default, not by what any other citizen says you are.
If you must have such a strained comparison think of a nation as more of a donut-of-the-month club (you belong or you don't) than a bridge club (you belong if they want you to belong).
Anyway, unless there's some significantly consequential difference between self-identifying as a Nation or being externally-identified as a Nation, this is getting to be quite the silly rabbit hole.
You've established that you're a good person for advocating on the side of legitimacy in nationhood. Let's move on with the topic of the OP.