Ok, but forget the "real" NFT's :-) because Apple doesn't allow to pay for an NFT without using the ApplePay. Otherwise they can not get their percent regardig the payment.
As you mentioned the physical items must be delivered or contracted about the ownership. It this case the full donation campaign for Ukrainian children was illegal, because phisically the same items were relisted despite of that the actual "buyer" already paid for it (this was the donation).
On the other hand in many cases when you list an item in ebay, it doesn't mean that the photo is about the actual item you listed. So there is no chance to identify the actual item (see not just eBay, but Aliexpress or Alibaba).