No both are still true and not conflicting at all.

Borders are imaginary lines. Some first Nations had shifting borders based on availability of certain resources, like one nation was able to fish up to a certain point on the river when the salmon were there but then when there wasn't salmon another nation had the right to hunt and gather berries or whatever.

You are a wild bison, roaming around and eating grass, taking shits where God says you shall. Then a white guy kills your entire family and builds a Walmart.

Borders are imaginary lines with very real consequences imposed by the state’s monopoly on violence.

For Special Big Trumpie it works this way. The border in the south is a huge deal, but the border with canada is just an imaginary line.

while land cannot be truly owned, it can be in use by people,

What can be "truly owned", and what does that entail?

If somethinɡ is merely "in use" by someone, can it be stolen from the user?

What is stealing? Doesn't stealing, as we intuitively understand it, presuppose (depriving someone of) ownership?

Let's say we find ourselves in this situation: you've loaned a book from the library, and someone stole it. Intuitively we might say the book was stolen from you. But that's mainly because it was temporarily associated with you; you didn't really own it, the harm for you is lesser than it would be if a book you bought was stolen, and more substantial harm affects the library that legally owns the book.

The book is stolen from the library. That's bad for the library. The land is stolen from...? Who is that bad for?

The analogy can only go so far, of course. The actual details of how Native Americans'(?) land was stolen include stuff like

Past treaties that had transferred land ownership employed a wide range of unethical or illegal tactics. Clauses, written in English but never mentioned to the Native signers, might appear in the “official” document.

Illegitimate “chiefs” also signed treaties. The Creek complained bitterly in 1825 that the Treaty of Indian Springs, which sold virtually all of the Tribe’s remaining land, had been signed by individuals not authorized to make such a sale. The Federal Government’s negotiators were well aware of this. The Tribe’s senior leaders had refused to sell and left the negotiations. After the senior leadership had left, the negotiators turned to the few remaining minor chiefs and persuaded them to sign the treaty.

https://www.cmich.edu/research/clarke-historical-library/explore-collection/explore-online/native-american-material/native-american-treaty-rights/land-transfers

Which is all basically theft through deception and similar. But to judge it that way we do have to already assume that the Natives owned the land that they were then cheated out of...

The imaginary lines are enforced with threat of/actual violence, and in doing so thieves people outside those lines of use of the land.

The borders are how they steal the land.

You just prove why I can't remember my left from my right, you literally posted the left on the right arm.

And I still can't grasp what the fuck left vs right means in political terms.