I find the concept of a technology that allows the transfer of ownership of digital artifacts fascinating. However, NFTs in their current form do not allow that

I find the concept of a technology that allows the transfer of ownership of digital artifacts fascinating. However, NFTs in their current form do not allow that. They are just systems that logs who "owns" the token for an item. This is quite useful for proving that a physical item (e.g. a piece of art) is genuine (or in fact proving that the person who is selling owns at that point of time a genuine version of the item), however that does not work for digital arts for the following reasons. What does it mean to own a digital item? I think that a minimal definition should include a unique access to it/or its capabilities: people who own the item are the only ones who can access it. Clearly, the current system does not allow this (everyone can access a picture sold as an NFT). Moreover, it is not clear whether such a system can be built for digital items. In fact, it seems to me, that a system that transfers the ownership of digital items can only work if the items cannot be copied; if I buy a digital item, copy it, then sell it, I still own it after selling it, which means I did not transfer it. This brings the question, what are the properties of items that cannot be copied (or are hard to be copied)? Complex systems could be such examples. For example, neural networks where inferring the network is extremely hard to be done from input and output. Assume that the item is a neural network that can generate a voice of an artificial character, or an interactive 3d model of an avatar. If, the system gives me exclusive access to the network, I would be able to use it to generate the voice or the 3d model of my avatar in a metaverse, however, I would not have access to the code that generates this data, only to the results of this simulation. TL;DR A digital ownership system (like NFT) is only meaningful for items that cannot be copied. These can only be complex systems where the ownership scheme gives access to the output of the system and not its totality (think voice generation system)