I'd be okay with open borders IF -
A) All people down to the last individual worldwide seceded from all states and became their own individual state.
B) Under international law (police force paid for voluntarily) there will be no use of violence or intimidation (by any group or individual) to coerce any non-violent groups or individuals to do or not do anything.
C) All individuals are free to do a they please so long as they agree to (B) - the said non-aggression principle.
All violent/coercive people would thus be eliminated from the international community of planet earth in relatively short order and we would forever live peacefully with free markets and voluntary communities.
People still are infatuated with Statism however so this is unlikely to happen sooner than 50 to 100 maybe even 200 years if we don't destroy the planet before that.
If my stipulations- A, B, and C aren't met then I will vigorously oppose open borders and will defend the right of nation states to exist in a fierce opposition to the push for a global state.
Open borders have brought nothing but disaster for Western Europe. They are committing cultural suicide by mass importation of people who choose not to assimilate in their new home, but to dominate.
The leaders of Western Europe are so blinded by political correctness and virtue signaling, they will never publicly admit that their policy of open borders is a bad idea. They will learn the hard way.
You didn't read it did you... FAIL