In the name of God, the Beneficent, Most Merciful
All praise is due to God (ﷻ), the Lord of the Worlds. The Beneficent, the Merciful. Master of the Day of Judgement, and God’s Peace and Blessings be upon Muhammad (ﷺ), his family, his noble Companions, and all those who follow them.
Your question: Was prophet Muhammad best of all prophets?
Answer: First of all, you cannot say like this because it is not nice at all. Ask yourself “how will the Prophet respond to this? How will Moses or other prophets respond you this?” I don’t think they’d like to hear this from you, why? Because all of them are important to us all and we cannot say that this prophet is better than this or that, no. That will go against Quran, because God Said:
”Say: We have believed in God and what has been revealed to us and what has been revealed to Abraham and Ishmael and Isaac and Jacob and the Descendants and what was given to Moses and Jesus and what was given to the prophets from their Lord. We make no distinction between any of them, and we are Muslims in submission to Him.”
(Surah Al-Baqarah 2:136)
This is the general rule regarding our attitude towards the Prophets and Messengers, and our Prophet specifically forbade us from saying that he is better than some other prophets. Even Muhammad forbid us to say that he is better than others, remember this:
”Whoever says that I am better than Jonah son of Mata has told a lie.”
This what Muhammad said in Quran. The only thing that we must believe is, that all the prophets and messengers are the best of the best. God Said:
“Say (O Muhammad صلى الله عليه وسلم): ‘I am only a man like you. It has been revealed to me that your Ilâh (God) is One Ilaah (God __ i.e. God). So whoever hopes for the Meeting with his Lord, let him work righteousness and associate none as a partner in the worship of his Lord’”
Abu Hurayrah, narrated that the Messenger of God ﷺ said:
”I will be the leader of the sons of Adam on the Day of Resurrection, and the first one for whom the grave will be opened, and the first to intercede, and the first whose intercession will be accepted.’”
CONCLUSION: We only say what God tells us, if He were to tell us that Muhammad is the best of all prophets than yes, it would be permissible but as long as He didn’t Said this, then no it is not permitted at all. And we should say that all the prophets and messengers are the best of the best.