I think this is the core problem, but you could allow freedom of movement without completely eliminating real estate.
On land you don’t own, you could be restricted to “leave only footprints, take only memories” and we could still mostly eliminate administrative borders.
This is impossible without also abolishing the concept of land ownership. Which I’m all for, but that ship sailed like 10 000 years ago.
I think this is the core problem, but you could allow freedom of movement without completely eliminating real estate.
On land you don’t own, you could be restricted to “leave only footprints, take only memories” and we could still mostly eliminate administrative borders.
Maybe not the best links, but here’s something:
https://www.visitfinland.com/en/articles/finnish-everyman-rights-the-right-to-roam/
https://finland.fi/life-society/how-every-persons-right-in-finland-evolved-over-more-than-a-century/