But what exactly are the rights you get when you buy an NFT? I'm assuming the absence of any other communication here, as that part would then be more like a verbal contract.

The NFT is a link to something, and buying the NFT means I get the ownership of the NFT. But I've no idea what this actually means in the end, which rights do you get by that? I paid someone $100 and got a link back, everything else is completely unclear. I've no idea how a court would be able to fill in all the blanks here.