Congregation in the mosque according to the clock schedule and the Sunnah of the Prophet 5375922187

There was a mahfil in the mosque of our area a few days ago. After Asr, Mr. Moazzin announced that Isha Jamaat will be held at 8.30 pm today. At eight-twenty in the night, one of the Ways said, "There was no clock in the time of the Prophet (peace and blessings of Allaah be upon him)." Iqamat was given when the perennial worshipers appeared. Today, on the occasion of this mahfil, we will now start Jamaat to revive this Sunnah. Since the mosque was full, the iqamah took place at 6:20 p.m. The second and third floors of the mosque were still empty. Due to the announcement that the congregation will be at 8:30 am, many of those who showed up at the appointed time did not receive the congregation. Many have been monthbooked. Now I want to know, did the Sunnah of the Prophet (peace and blessings of Allaah be upon him) come to life after giving Iqamah ten minutes ago, or should the congregation have started at 7:30? If it is bid'ah to start the congregation at a certain time according to the time of the clock, then should the congregation start as the time of the clock by hanging the prayer schedule in every mosque? 8492788866