I’m not aware of any legal protections available to the person holding the private key that last signed an NFT. Digital property rights are enforced by client apps / DRM as well as legal trade agreements, but legal enforcement will be based on traditional registrations and won’t cover on-chain NFT transactions. You can buy my house’s NFT, but I will still legally own my house. Since, as you point out, DRM can always be broken, there is effectively no enforcement of NFT property rights at all.