Islam popped up six centuries after Jesus. Mohammed mixed Arab paganism, some Rabbinic Judaism and elements of Gnostic “Christianity” together and turned that all into Islam. The concept of “jihad” was the only way he could make Islam spread.
If Islam were so swell, God would not have sent Christ Jesus, nor would he have He been judged on the Cross, nor would he have been resurrected
Considering the Bible says there is nothing new under the sun, you are probably right. Islam is, most likely, just a mix of different false religions, all put into one.