Blockchain / NFTs do not solve proof of ownership. Just ask all the people who had their NFTs or crypto stolen or lost in scams.

In your example, technically title fraud is more difficult because it needs to be done in two places. In reality it becomes far, far easier because you've now opened up a gigantic attack surface that you have no control over, and made both systems of verification worth less. If someone manages to compromise either one, there goes your proof of validity. Which one of them is real and which one is fraudulent?