How sound is the hadith that reciting Surat Al-Ikhlas three times on the minbar is sufficient in place of the Friday sermon? And what should be done if the Imam repeatedly absents himself and does not deliver the Friday sermon?

If the Friday preacher is absent, those present are obligated to put forward one of their own to lead the prayer, and he should deliver the sermon to them, then lead them in the two-rak'ah Friday prayer. It is not permissible for them to abandon the sermon and pray Dhuhr as four rak'ahs instead. The sermon is valid with the least amount of speech that includes the remembrance of Allah, admonishing and advising those present, such as praising Allah, reciting one or two verses [of the Qur'an], enjoining piety, and sending blessings upon the Prophet (peace be upon him). Merely reciting Surat Al-Ikhlas (definition) three times is not sufficient; rather, the least amount of speech that can be described as a sermon, and which includes praising Allah and enjoining those present to adhere to Allah's law, must be delivered. If people pray Dhuhr instead of Jumu'ah due to the absence of the preacher, their prayer is not valid unless the time for Jumu'ah has expired, according to the majority of scholars. Therefore, your Dhuhr prayer instead of Jumu'ah is not permissible and not valid, and you must repeat it. If this situation recurs, the obligation is for one of those present to deliver the sermon, or for them to go to another mosque where the Jumu'ah prayer is held.