What is the nature of the personality of Prophet Muhammad, peace and blessings be upon him, and how can he be the best while being compelled to deliver the message? And did he have a choice in that?

Our Prophet Muhammad, peace and blessings be upon him, is the best of all creation. It is authentically reported from him, peace and blessings be upon him, that he said: "I am the master of the children of Adam, and no boast. Adam and all those below him will be under my banner on the Day of Resurrection, and no boast." As for the obligation of conveying the message upon him, peace and blessings be upon him: this responsibility contains an honor for him and does not contradict his chosen status and excellence. For among his characteristics is his prophethood to both humankind and jinn, and Allah Almighty said: {Blessed is He who sent down the Criterion upon His servant that he may be to the worlds a warner}. And indeed, he was sent to all people generally. It is also said that he was sent to all prophets and previous nations.

And Allah knows best.