Is completing the recitation of the Qur’an in congregational loud prayers every five days, in a private mosque, in accordance with the Sunnah?

What the Imam does by reciting the Quran in prayer according to the order of the Mus'haf is considered desirable by some scholars, while others permit it on condition that it is not believed to be a Sunnah. As for prolonging the obligatory prayers, if the congregants are limited in number and agreeable to it, then there is no harm, and it is even desirable at that point; otherwise, the Imam should not prolong it.