What if the relay and target are being operated by the same provider? The relay controls where the question is sent right? They can collude?

no, you are actually telling the relay where to redirect your question from the start (because you are encrypting the question with the public key of the destination resolver) - the relay sending the question where it wants would result in the destination to not be able to decrypt it

If relay and target are operated by the same provider, there is no collusion. Collusion occurs between 2+ parties. You have stipulated that they are the same party.

"They can collude?"

There are no limitations on what these parties can do with the data they collect or where they can transfer it