What is the reason for considering a prayer valid with only the Fatiha, even though the actions and Sunnah of the Prophet, peace and blessings be upon him, indicate that he used to recite the Fatiha and a short surah after it?

First: Your statement that the Prophet did not limit himself to reciting Al-Fatihah in a rak'ah is incorrect, based on the hadith narrated by Abu Qatadah, agreed upon [by Al-Bukhari and Muslim]: "Indeed, the Prophet used to recite the Opening of the Book in the last two rak'ahs."

Second: The hadith: "Pray as you have seen me praying" is interpreted as imposing obligation for obligatory acts, and recommending for supererogatory acts, based on the context of the hadith of the one who prayed badly. On this, there is a consensus among scholars, contrary to the apparent command of obligation.

Third: Reciting a surah after Al-Fatihah is supererogatory and not obligatory, according to the consensus of the people of knowledge; based on the hadith narrated by Abu Hurayrah, agreed upon [by Al-Bukhari and Muslim]: "And whoever recites the Mother of the Book, it suffices him, and whoever adds more, it is better."

Fourth: Reciting tasbih seven times in ruku' has not been established in the Sunnah. Making tasbih obligatory in ruku' and sujud is the view of the Hanbalis, while the majority consider it supererogatory. The Hanbalis based their argument on the command mentioned in the hadith of Uqbah ibn Amir, even though there is some discussion regarding its chain of narration.