Even if it were possible, I don't think there's a way to do it in a way that would make any sense. Would we set up an AI now and then forever use the same one? In that case people will learn any small quirks of the AI and optimize against those vs human play, fundamentally changing the game. If the proposal is to be constantly updating this AI, well even in that case I'd argue that people will over time identify any small difference between machine and human play, but in that case people will also be upset that someone got normed against the "easy" AI, or against the AI that didn't know about the dumdenmorph-joyce-allens countergambit yet, etc.

That kind of engine exists! It's called Maia, as mentioned in a sibling comment.

https://maiachess.com/