What is the difference between the first congregational prayer held in the mosque and the second congregational prayer of those who arrive late, and does the acceptance or reward differ with the number of participants?

Initiating prayer is one of the best deeds, and there are hadiths that indicate this, such as: "Prayer at its appointed time" and "Frequent steps to the mosques." The basic principle for a mosque is that only one congregation should be held in it to preserve the unity of Muslims. However, if a group arrives after the prayer has finished, they are permitted to pray in congregation. It is better for a Muslim to take the initiative and pray with the first congregation due to the promptness in doing good and hastening to it, and because a second congregation is not guaranteed. A Muslim should not delay or be lazy relying on catching a second congregation. It is worth noting that some scholars have deemed a second congregational prayer in the mosque as disliked, and it will not reach the level of the original congregation.