No one can definitively prove that there's no connection between the prefix and the private key—just like you can't conclusively prove that there is any relation.
So in my opinion, it would be better to pause this debate until either side can bring stronger evidence. Right now, it's just unnecessarily stretching the thread without any productive outcome.
All 3 steps in the algorithms are designed so that there is no connection. It’s part of the basic properties of a hashing function and of an elliptic curve. Having a connection means there is a different flaw in all 3. So unless people come up with a proof of each of those flaws, then they is no link. Not the other way around.
Agree on not talking about it anymore, given how something so obvious is hard to understand for some.