I’m not really very interested in borders one way or the other but national borders certainly aren’t “artificial.” There are certainly some artificial aspects (lines of longtitude, etc) but borders are also created by geography and culture and saying that culture is artificial is odd to me. There are distinct peoples with different values. We also have lots in common as humans, but the border of France and Germany, for example, is very real and those countries have different cultures.
I think the EU is a good example of improved relations between countries but it’s certainly fine and not some sort of mental disorder to think that Switzerland and Italy are different and it’s fine that they are different.
If nations want to have distinct boundaries and populations then there should be an avenue to respect human rights and not resort to racism and undue nationalism. It’s also a good time to point out that immigration has been essential for major countries and is a very powerful positive force.