I never get upset with you :-) I think, we humans are created with the tendency of holding divergent views. If God had willed, He could have made all mankind holding similar views.
10:19 All mankind were but one community (and are meant to be so); then they differed. Had it not been for a Word that went forth from your Lord (the Law of Free Will), He would have judged their disputes immediately. [2:30, 2:213, 2:256, 11:118, 16:9, 76:2-3]
11:118 Had your Lord so willed, He could have made all mankind one single community, (but He has granted them free will as against other creatures who are driven by instinct). Therefore, they will continue to hold divergent views. [5:48]
Please read my post again. The name Muhammad appears in the Quran at many places.
Surah Muhammad is Surah Muhammad.
Many names are nouns as well as adjectives. Look at your own name SAIM.
Muhammad = Praised one.
Muhammadin, Muhammadun only carry a kisra and dhamma (short vowels) = Muhammad IS.
Muhammad-ur-Rasulullah = Muhammad IS the messenger of God.