What are the 4 "winning" first moves assuming perfect play?
it is pretty darn obvious that they are no winning moves on move 1 even with God play. More interesting is if they are any losing moves from move 1, but even then, it looks unlikely. The worst white moves are no worse in eval than some of the ok secondary defenses for black.
with black however, the question is more controversial. is 1.e4 b5 losing by force? what about 1.e4 f5 ? I would like to see how well naka does vs komodo with 1.e4 f5.
The most popular first moves are 1. e4, 1. d4, 1. Nf3, and 1. c4. Other moves are less popular, but a number of them are perfectly fine. I'd throw 1. Nc3, 1. b4, 1. g3, 1. b3, and 1. a3 into this category. Bird's opening, 1. f4, is sound, but you really need to know what you're doing to try it, because bad things can happen very quickly if you don't.
The other moves are either clearly inferior to others, such as 1. e3, 1. d3, and 1. c3 or have a weakening effect on your pawn structure, and I'd count 1. f3, 1. h3, 1. h4, 1. g4, and 1. a4. Taking a knight to the edge of the board with 1. Na3 and 1. Nh3 weakens your center.
The second group of openings, as well as the Reti (1. Nf3) and the English (1. c4), are more difficult for the beginner to learn, because they require hypermodern concepts to play successfully. Both 1. e4 and 1. d4 can be put to reasonably good effect with classical positional principles alone.
If you asking
what is the « 4 winning » first moves assuming perfect play to Magnus Carlsen who is the world’s champion I don’t think he could answers to this question easily, I mean you have not need to know perfectly an opening because there are too many openings who exist at chess. By exemple I know GM who played 1 e3 against a master and with this move the game was similar to French defense so it’s difficult to tell they are « 4 winning first moves » And also you have players who played 1 e4 other d4 and c4 etc so it’s depend of the player’s style also