Looks like that's Real Madrid's new strategy of getting players that they want without playing expensively for it. Look at how they signed Mbappe, and this summer Trent. Seems similar thing will happen to Konate when his contract expires next season. Real Madrid approaches the players one or two season before the end of their contract in their club and it is working for them.
Every club normally reaches personal agreement with the players most of the time which is very legal. You are wrong about Mbappe because over the years Perez has wanted to sign him and PSG refused because he was their prized asset. Real Madrid offered PSG €180 million two years ago but they refused and said his not for sale thinking they can convince him to stay, but that was the last offer and Perez told them that he won't attempt to buy Mbappe again and they will lose him for free. Of course he already knew that Mbappe wanted to play for Real Madrid. When you know a player wants to only play for your club, then you will have guts.