I just think that’s a strange criteria for which to deem a game “perfect.” But if that’s where you’ve been going with us the whole time, I don’t disagree with you.
My first foray into this topic I started off by not using this definition of perfect.
You politely informed me that only two real evaluations exist (I agreed) and if it never changes the whole game then it's a perfect game (I agreed).
Why you suddenly want to use a different definition of perfect I don't know, but I agree that the one we've been using isn't anything like the colloquial way we talk about a perfect game.
And even if it determined every position from start to finish was drawn, let’s say on move 20 White had a candidate move that would’ve been assessed +1.16, but instead chose a move that was assessed 0.08. Did he play the perfect move?
Taking into account conventional engine evaluations this would lead to a much more pleasing definition of perfect.
But it's also a lot harder to properly define.
First of all, moves that are difficult for one opponent may be easier for another. How do we quantify this?
Secondly if we only go by "difficulty" then there's the problem of games won due to purposefully giving yourself a losing position (like some king's gambit variations) but for the purpose of greatly increasing the chance of a blunder from your opponent.
I’m speaking from the standpoint of objectivity. The objectively best, most perfect moves. The thread topic, chest being solved. Who sits on the other side becomes irrelevant. Psychology becomes irrelevant. Mathematically, what is the objectively best move, which will achieve the most desirable outcome of the game.