Ruling on reciting al-Fatihah before the imam recites it

Q: The questioner, brother A. M. S. from al-Hufuf in the Kingdom of Saudi Arabia, says in his question: The imam sometimes delays starting to recite al-Fatihah in the loud prayers, which allows me to recite al-Fatihah before him. Is my action in accordance with the Sunnah, or is it necessary to recite it after he finishes reciting it? Please issue a ruling for us, may Allah reward you with good.

A: It is obligatory for the ma'mum to recite al-Fatihah in all rak'ahs. If it is possible for him to recite it during the silence of his imam, before the imam recites al-Fatihah or after he does, that is better. If that is not possible, he recites it even while the imam is reciting. Then he listens, based on the saying of the Prophet (peace and blessings be upon him): We said: Yes. He said: It was narrated by al-Imam Ahmad, Abu Dawud, al-Tirmidhi, and Ibn Hibban with a sound chain. And based on the generality of his saying (peace and blessings be upon him): It is agreed upon that it is authentic from the hadith of 'Ubadah ibn al-Samit (may Allah be pleased with him).
However, if the ma'mum leaves it out due to forgetfulness or ignorance, his prayer is valid; because it is obligatory for him, not a pillar. Likewise, if he arrives and the imam is bowing, or if he bows with his imam at the time of bowing, al-Fatihah is dropped from him. This is based on what al-Bukhari narrated in his Sahih from Abu Bakrah al-Thaqafi (may Allah be pleased with him) that he came to the mosque and the imam was bowing, so he bowed without joining the row, then he entered the row. The Prophet (peace and blessings be upon him) said to him after finishing the prayer: And he did not order him to make up the rak'ah. This indicates that he is excused if he does not catch the imam in a state of standing in a way that allows him to recite al-Fatihah. The ignorant person and the forgetful person are in his ruling in meaning. This is unlike the one praying alone and the imam, for whom it is a pillar that is not dropped from them in any way, acting in accordance with the authentic hadiths narrated regarding that. And success is from Allah.