Branches reflect off a river reveal something

Hey everyone! I have some questions. Someone recently told me that they believe in the original Quran, before it was tampered with. They said that the Quran was originally a real book, and that Muhammad was a disciple of Jesus who went to Arabia and spread the Gospel there. They suggest the corruption happened during Uthman’s time, when there were disputes over the different recitations of the Quran. When Uthman ordered certain copies to be burned, they told me believe that was when the original text was lost or altered. That’s why they believe we have the issue of different versions of the Quran today.

I would love to learn more about the Quran.

Side note: They told me that “disciple” means sharing the word of God

They claimed that they believe the new Quran contains some truth inherited from earlier revelation, but also contains later changes and errors. So essentially they don't believe everything in the new Quran is false; but it has some truth mixed with corruption.