Complex sentence: However, tension was growing among the band members as a result of the increasingly Christian perspective of his lyrics; he was increasingly dissatisfied with the band's musical direction (at least in part due to his newfound faith); and Steinhart left the band.
Split into simpler sentences: However, tension was growing among the band members as a result of the increasingly Christian perspective of his lyrics. He was increasingly dissatisfied with the band's musical direction (at least in part due to his newfound faith) and Steinhart left the band.