The first suggests that there is one particular move that is better than yours that you are learning from. If you want to invoke its moves in general being better than yours, you should use the plural.
While it is true that "a bot's move is better than yours" can be understood as being a general statement that can be applied to any of the bot's moves, its focus is on one move. That is, it is saying "If you pick any of the bot's moves, that one move will be better than yours." It's general it the sense that it applies to all of the bot's moves, but specific in the sense that once a move is picked, it applies to that one move. This probably sounds confusing, and usually this difference isn't important, but there are cases where the different types of generalizations do matter, and this is such a case. There's a difference between saying "If you pick one of the bot's moves, it will be better than yours, and because of that you can learn from the bot" and "All of the bots moves are better than yours, and you can learn from that". The first sentence makes it sound like just one move being better is enough.