Neither can play DM.I watched Ndomeble before this lad came along in that position and he was just as good, the reason Ndombele moved further forward was because he had the capacity to do so, if we want a DM Aouar can do a job but if we want a Fernadinho back up Ndombele is the one
Aouar doesn't have the workrate and isn't physical enough, Ndombele doesn't like defending or playing in a defensive position and has said it in interviews many times.
You can't turn a player who has never defended much and doesn't like it into a Fernandinho replacement.
Furthermore Ndombele was a striker when he was younger hence why he is far more offensive, he also has the mindset that he shouldn't have to defend against smaller clubs.