The presence of Kylian Mbappe in the Real Madrid team I believe will make the manager to change from the playing formation he used last season so he can accommodate the France striker in his regular starting XI. Real Madrid last season mostly played four midfielders while playing a front two of Vinicius Jr and Rodrygo as Bellingham was allowed to play in the false 9 position but with the arrival of Kylian Mbappe, I expect Real Madrid to go back to a front three attackers and three midfielders.
Carlo Ancelotti have proven over the years with his incredible success in football that he has all it takes to manage any team regardless of how talented it appears to be so I believe he already knows what to do with the Real Madrid team
I agree better with your closing statements, Ancelotti knows better based on his experience on how well he's going to be able to handle his team and still achieve great success with them, most definitely adjustments will be made to allow the French international fit in the Madrid squad in the new season. Very importantly is it that they now have a striker so for vinicus and Bellingham it's a sign of relief as they will be back at their original positions and not having to alternate for the top nine.