The virtuoso violinist who rose to superstar status, in part by cultivating the rumor that he had sold his soul to the devil in exchange for phenomenal technical abilities, was franz schubert.

This statement is False

The person who is in question here is actually Niccolò Paganini, an Italian violinist and a composer. The rumor was actually supported by himself since he participated in the rumors for various reasons, mostly humorous. He was one of the most important persons in history of fiddling because of how he modernized the play-style.