There are no rights, just a bunch of nations all acting in their own interests. Often, these interests align, and that gives the impression of "rights".
That is a cynical view of things. But a pragmatic cynic might also recognize that sometimes it's useful to take a made-up concept like "rights" and repeat it over and over and over again until everyone forgets it's made up. Because at that point it becomes part of reality, just like the concept of nations or constitutional rights or laws did.
Just like we build physical infrastructure to make our lives better, we can and do also build social infrastructure. So the question is not whether "rights of nations" in general or in some specific set are "real" or merely an illusion, the question is whether they're useful.
As technology continues to advance, and weapons of mass destruction come ever easier to come by by anyone feeling slighted, continuing power politics is a road to extinction. Of course, that doesn't mean people or nations will necessarily give up them upr; but I think it's likely that any possible future that has people will also have a world system based on law, not might. How likely such bright futures are, compared to those where the world burns to cinder, is another matter.