He should be used as a mobile left winger, allowing him to come inside very often. Him on the left and Yamal on the right is ideal in this sense, because on the left Balde can push up and eat space given if Raphinha's marker follows him around and leaves his position.
On the other side, Yamal has to do a lot more on the ball closer to the sideline, because Kounde is a defensive fullback mostly.
Often times managers play the wingers closer to the line in build-up also because it's a handy and easy option for the fullback to just pass it down the line if under pressure. Without this pressure release option, the job of the fullback becomes more complicated, which is why important to have one that is technically gifted. He has to play inside more, and this is obviously more risky. This is also why you need 2-3 players to drop constantly to provide passing options inside, not just one. Of course moving more, dropping more, making more actions to make yourself available is more taxing in terms of effort, and requires more physical training.