Is "No one legitimately contests what another holds and uses" any better? Probably not, but it's what I should have said. All the same, an idea of property as such isn't required. I'm not substituting that phrase for "property". I'm falling short in not having it look that way, which it still does.

Okay, but like, is it bad if I make myself a sandwich and someone comes over while I'm cleaning up and takes my sandwich? And if so, what is the idea or principle that's being transgressed?

No because I don’t think that statement is true at all. I think there are many case where someone holds and uses something and, actually, they shouldn’t have that thing. Saying “actually, property isn’t real if you think about it” doesn’t help to materially address that conflict