How would such engine work? Chess engines work by evaluating a lot of positions. But in order to evaluate a single Human Chess position, you need to run a normal chess engine for a minute to determine the top move.
I think you overestimate how much you would have to defer to this external engine that would have to say which move is "top".
Every move you advance you chessboard situation by one move only and that move is already part of the tree calculated previously. You don't need to search through massively more new moves because, assuming sane players, the move each player makes is one of the very few top moves previously considered by the engine.
In other words, whatever the rules, you can have an engine that will try to do the best according to the rules.