Although the 4-1-2-1-2 formation was also used against Real Sociedad and at that time Real Madrid won. But there is something different about the 4-1-2-1-2 formation that was used in the match against Atletico Madrid. The reason is that Carlo Ancelotti's player placement is different from when he played against Real Sociedad. Even Bellingham was placed in a position that was not really a suitable place for Jude Bellingham. He is more comfortable in the middle than in that position.
I agree with you, the problem with the formation is that Ancelotti rotates several players, but apart from that another problem is the limited number of players that Madrid has, from strikers to defenders who lose in the fight for the ball. Morata as a former Madrid player made Ancelotti speechless. Madrid deserved this defeat because, in terms of the game Atletico Madrid was superior. This defeat will be a major blow when the main players are injured and the replacement options are not suitable, which could cause Madrid to experience a setback. Valverde and Bellingham, who usually appear solid, were actually prevented from moving freely and were closely guarded by their opponents.
And yes, that's another problem that Real Madrid is currently facing. Namely the limited number of second tier players who are competent enough who can replace the main players when they are injured. And another problem is that J.Bellingham is now being guarded more often by opponents. This is similar to what happened to Haaland at Manchester City. Haalang was very productive at the start of his career at Manchester City. But then opponents began to realize the dangers of Haaland without tight guarding. So he was always closely guarded. And now it seems Bellingham will also experience something similar to what happened to Haaland.
Fortunately, in Real Madrid's next match, Vinicius Jr should be able to help strengthen the Real Madrid squad again. Because of the muscle injury I think by now it should be healed.
It's just that now Girona appears in 2nd place without anyone expecting anything at all. This happens because Girona have not met a club that is tough enough to stop the positive trend they are currently having.
The reason is that in the next match Madrid will meet Girona who is in their best performance. It would be very disappointing if Madrid lost to Girona. With Girona's current record of being unbeaten in a total of 6 matches, their winning trend will continue to be maintained as much as possible.
If Real Madrid is unable to beat Girona then of course it will be another surprise in Laliga. Girona themselves will certainly do their best to maintain their positive trend. But I think it will end up in Real Madrid's hands.