Try to think in terms of individuals, not nations. As for your sovereignty - it ends outside of your condo - you can't restrict someone from Oklahoma to move to SF.
There is no such thing as a sovereign individual. Unless you refer to the Libertarian cranks hassling cops on YouTube.
In practice, nations can restrict people from moving if they choose to. Perhaps mine won't, but China certainly will.
The reason, by the way, that Oklahoma and California can't restrict migration between them is that US states are not sovereign. The original colonies ceded essential parts of their sovereignty to form a national federal government. This is US history 101.
Why do you have sovereignty over your condo? Why can't I express my right to sleep on your couch, regardless of your consent? If you can express access control rights over a particular piece of territory or property that you consider your own, then why can't a collective group of people also express access control rights over their common, government-managed and administered property/territory?
I think there's enough responses in the thread regarding open borders that I won't belabor that point again. To the question of birthright citizenship, I'd probably be ok with eliminating it if we replaced it with service-based citizenship a la Starship Troopers (to include volunteering in the Peace Corps, volunteer firefighting, and maybe law enforcement). But it leads to the question of: if people (including native-born ones) don't meet the citizenship requirements, do they become stateless persons? Do we deport them? To where?
https://www.liberties.eu/en/news/why-refugees-do-not-take-th...
https://blogs.berkeley.edu/2016/02/11/why-dont-refugees-fly/
>>>but in order to qualify for such status they need to be [almost] drown in the sea or [almost] killed at the border.
There's not much we can do about natural geography. I'm not sure what alternative course of action is suggested in the case of, say, Cuban or Haitian refugees attempting access by boat. Secondly, no one is "almost killing" refugees that show up at designated legal points of entry to the country. Finally, anyone other than Mexican citizens attempting to seek asylum/refugee status by crossing the US-Mexico border is probably in error (I wouldn't go so far as to say "not acting in good faith").
Consider this from: [1] "Once refugees or asylum seekers have found a safe place and protection of a state or territory outside their territory of origin they are discouraged from leaving again and seeking protection in another country."
In other words, Hondurans/Guatamalans/etc... should not be transiting Mexico to seek refugee status in the US to begin with.[2]
[1]https://en.wikipedia.org/wiki/Refugee#Restriction_of_onward_...