Was Marwan ibn al-Hakam a Companion of the Prophet, and did he play a role in the caliphate of Uthman and the events of the Fitna?

Marwan ibn al-Hakam was born during the lifetime of the Prophet, peace and blessings be upon him, and Ibn Hajar counted him among the Companions who saw the Prophet, peace and blessings be upon him. He was accused of involvement in the events of the tribulation (Fitna) that led to the criticism of Uthman. However, the contemporary Muslim should focus on reforming himself, his society, and his era, and refrain from delving into the disputes that occurred among the predecessors. Scholars have agreed on praising the Companions and refraining from discussing what happened between them, and that they are the most deserving of having the best interpretations sought for their actions and the best assumptions made about them.