Complex sentence: The Harlem Hamfats were not thought to be the most innovative group of the time, and many of the band's original works dealt heavily with sex, drugs and alcohol, which may have hindered their music from being more widely available.
Split into simpler sentences: The Harlem Hamfats were not thought to be the most innovative group of the time. Many of band's original works dealt heavily with sex, drugs and alcohol, which may have hindered their music from being more widely available.