عملنا بهما على وجه لا يتغير به حكم الكتاب
Both proofs are applied in a way that does not change the character of the Qurʾānic rule.
The general Qurʾānic obligation establishes basic recitation. The report about al-Fātiḥah is not discarded; it establishes a distinct special requirement.
This is one form of reconciling proofs: giving both texts a legal role instead of treating one as cancelling the other altogether. The schools still disagree over the sound interpretation and its consequences.