What is the ruling on the imam supplicating aloud, facing the congregants, after the prayer?

Supplicating after prayer is permissible and lawful. Imam al-Bukhari titled a chapter "Chapter: Supplication After Prayer" and mentioned remembrances that the Prophet, peace and blessings be upon him, used to recite after concluding the prayer. Al-Hafiz Ibn Hajar refuted those who entirely denied the legitimacy of supplication after prayer, citing as evidence hadiths such as Mu'adh's supplication: "O Allah, help me to remember You, to thank You, and to worship You in the best manner," and the Prophet's supplication, peace and blessings be upon him, after finishing the prayer: "O Allah, set right my religion for me, which is the safeguard of my affairs..." Those who forbid supplication restrict it to cases where it occurs immediately after the salutation and before the prescribed remembrances. There is latitude in this matter, and no one should be criticized for supplicating or for not supplicating. However, singling out supplication with a specific characteristic, such as the Imam reciting it aloud and the congregants saying 'Ameen' behind him, and adhering to this and performing it regularly, is considered an innovation.