I'm sorry but you're not making much sense to be honest. What is the point of an asset-backed NFT when a NFT like a gem is an asset itself? They are stand alone items on the blockchain that do not need to be backed up by anything. Their market value could depend on the creator and level of its rarity.
I could not agree more than this, the value of NFT comes from its uniqueness and rarity. If you are going to back it up with other asset, you do not create something unique but rather you are creating a stablecoin. the reason it is called stablecoin because it has reserve to back up the price while NFT does not have and need such a thing to have a value.
simply put NFT can be called as a memento.