Should we get rid of borders?

I’m quite out of my depth here but I see quite a few people advocating for boarders between countries to be eradicated. My gut feeling says this would be for the better, legal borders aren’t natural, also most of my family are immigrants who can’t return to their homes because of boarders.

Maybe the world would be better without countries and boarders in general, if we had open administrative provinces or something similar instead. I do think that societies would function better if smaller localities were governed individually to an extent, not like a federation but like local councils. Maybe I’m romanticising the idea of kingdoms of the past but I think self sustaining municipality’s would be more environmentally sustainable and economically secure as well as community centred (in an ideal word where capitalism fucked off into oblivion). Ok maybe I’m going on too much of a tangent.

What are the pros and cons of open borders in the current economic and social climate of the world? I genuinely don’t know, this is something I’d love more insight on.