The Quran was Mohammed realizing that Arab culture was barbaric and using Christian and Jewish ideals to try to make it less so. Sharia was formed centuries after his death by Arabs mostly on rumors of what he is supposed to have said and done, and it basically re-introduced much of the pre-Muslim barbarity.
It’s nice to know Mohammed was really a nice guy!
You describe the early years of Mohammed. He quickly turned even more barbaric than the culture he fought, using his self-proclaimed "visions" to justify his barbarism. By 622 A.D. Mohammed's anger toward the Jews was not just rhetoric. The period from 622 C.E. until Mohammed's death in 632 C.E. was punctuated by periods of intense anti-Jewish violence as he systematically expelled, plundered and even slaughtered the Jewish tribes of Nadir, Khaybar and Banu Qurayza who lived in and around Mecca. Mohammed's victories of the Jews are discussed in great length in Sura 59 of the Koran.
He was also at war and Jihad against his fellow Muslims too. Once he had made Medina his stronghold, Mohammed mobilized an army of 10,000 men and, in 630 CE, moved against Mecca, meaning to purify the Kaaba and turn it into a center of worship of the one God, Allah.