Irrespective of whether or not they actually contribute to these injuries, stuff like Club World Cup and Nations League are utter nonsense. Let's get this out of the way.
But, as also evidenced by NBA players who are babied like never before yet still are not immune to going down with these horrific injuries from time to time, the main culprit IMO is the high intensity of the said sport that requires players to make so many sharp moves.
Gone are the days when players had the luxury of standing around or jogging during a good portion of the game, putting little to no pressure to their ligaments and muscles.