Is there a way to allow somebody else to mine a vanity prefix npub without letting them see the final private key?

Here's my thinking. I create a new Private Key by myself and I share its public key with a miner. The miner must find the private key that, when its npub is summed into mine, creates the vanity prefix I want. In that case, I can then buy the private key out of the miner, sum with mine, and have a new private key. The miner wouldn't have access to the new private key.

Does that work? Or am I missing something?

Does that mean we can create trustless mining markets that people can just take orders to mine new Nostr Keys and sell them? 🤔